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The 2004 season’s official transaction log: 1,478 trades, signings and releases involving major-league clubs, listed newest first.
| Date | Type | Player | From | To | Details |
|---|---|---|---|---|---|
| Dec 31, 2004 | Signed as free agent | Todd Hollandsworth | — | Chicago Cubs | Free agent signing |
| Dec 31, 2004 | Signed as free agent | Kevin Hooper | — | Detroit Tigers | Free agent signing |
| Dec 29, 2004 | Signed as free agent | Luis Lopez | — | Cincinnati Reds | Free agent signing |
| Dec 29, 2004 | Signed as free agent | Jorge Padilla | — | Philadelphia Phillies | Free agent signing |
| Dec 29, 2004 | Signed as free agent | Chris Woodward | — | New York Mets | Free agent signing |
| Dec 28, 2004 | Signed as free agent | Matt Childers | — | Atlanta Braves | Free agent signing |
| Dec 28, 2004 | Signed as free agent | Eric Milton | — | Cincinnati Reds | Free agent signing |
| Dec 28, 2004 | Signed as free agent | Abraham Nunez | — | St. Louis Cardinals | Free agent signing |
| Dec 28, 2004 | Signed as free agent | Jaret Wright | — | New York Yankees | Free agent signing |
| Dec 27, 2004 | Signed as free agent | Kirk Bullinger | — | Pittsburgh Pirates | Free agent signing |
| Dec 27, 2004 | Signed as free agent | Jacob Cruz | — | Cincinnati Reds | Free agent signing |
| Dec 27, 2004 | Signed as free agent | John Lindsey | — | St. Louis Cardinals | Free agent signing |
| Dec 27, 2004 | Signed as free agent | Mike Moriarty | — | Boston Red Sox | Free agent signing |
| Dec 26, 2004 | Signed as free agent | Greg Jones | — | Anaheim Angels | Free agent signing |
| Dec 26, 2004 | Signed as free agent | Andy Van Hekken | — | Atlanta Braves | Free agent signing |
| Dec 25, 2004 | Signed as free agent | Brian Falkenborg | — | San Diego Padres | Free agent signing |
| Dec 25, 2004 | Signed as free agent | Jose Lima | — | Kansas City Royals | Free agent signing |
| Dec 24, 2004 | Signed as free agent | Steve Cox | — | Tampa Bay Devil Rays | Free agent signing |
| Dec 24, 2004 | Signed as free agent | Mike Difelice | — | Florida Marlins | Free agent signing |
| Dec 24, 2004 | Signed as free agent | Jason Varitek | — | Boston Red Sox | Free agent signing |
| Dec 24, 2004 | Signed as free agent | Les Walrond | — | Florida Marlins | Free agent signing |
| Dec 23, 2004 | Signed as free agent | Micah Bowie | — | Washington Nationals | Free agent signing |
| Dec 23, 2004 | Signed as free agent | J. D. Drew | — | Los Angeles Dodgers | Free agent signing |
| Dec 23, 2004 | Signed as free agent | Chad Durbin | — | Washington Nationals | Free agent signing |
| Dec 23, 2004 | Signed as free agent | David Eckstein | — | St. Louis Cardinals | Free agent signing |
| Dec 23, 2004 | Signed as free agent | Andres Galarraga | — | New York Mets | Free agent signing |
| Dec 23, 2004 | Signed as free agent | Raul Gonzalez | — | St. Louis Cardinals | Free agent signing |
| Dec 23, 2004 | Signed as free agent | Seth Greisinger | — | Washington Nationals | Free agent signing |
| Dec 23, 2004 | Signed as free agent | Phil Hiatt | — | Washington Nationals | Free agent signing |
| Dec 23, 2004 | Signed as free agent | Orber Moreno | — | New York Mets | Free agent signing |
| Dec 23, 2004 | Signed as free agent | Luis Pineda | — | Washington Nationals | Free agent signing |
| Dec 23, 2004 | Signed as free agent | Grant Roberts | — | New York Mets | Free agent signing |
| Dec 23, 2004 | Signed as free agent | Julio Santana | — | Milwaukee Brewers | Free agent signing |
| Dec 23, 2004 | Signed as free agent | Scott Strickland | — | New York Mets | Free agent signing |
| Dec 23, 2004 | Signed as free agent | Reggie Taylor | — | Colorado Rockies | Free agent signing |
| Dec 23, 2004 | Signed as free agent | Chris Widger | — | Chicago White Sox | Free agent signing |
| Dec 22, 2004 | Signed as free agent | Matt Clement | — | Boston Red Sox | Free agent signing |
| Dec 22, 2004 | Signed as free agent | David Cortes | — | Colorado Rockies | Free agent signing |
| Dec 22, 2004 | Signed as free agent | Cesar Crespo | — | Pittsburgh Pirates | Free agent signing |
| Dec 22, 2004 | Signed as free agent | Jeff Harris | — | Seattle Mariners | Free agent signing |
| Dec 22, 2004 | Signed as free agent | Brandon Medders | — | Arizona Diamondbacks | Free agent signing |
| Dec 22, 2004 | Signed as free agent | Wade Miller | — | Boston Red Sox | Free agent signing |
| Dec 22, 2004 | Signed as free agent | Mike Myers | — | St. Louis Cardinals | Free agent signing |
| Dec 22, 2004 | Signed as free agent | Josh Phelps | — | Tampa Bay Devil Rays | Free agent signing |
| Dec 22, 2004 | Signed as free agent | Mark Sweeney | — | San Diego Padres | Free agent signing |
| Dec 22, 2004 | Signed as free agent | So Taguchi | — | St. Louis Cardinals | Free agent signing |
| Dec 22, 2004 | Signed as free agent | Jamey Wright | — | Colorado Rockies | Free agent signing |
| Dec 21, 2004 | Signed as free agent | Wilson Alvarez | — | Los Angeles Dodgers | Free agent signing |
| Dec 21, 2004 | Signed as free agent | Chad Bentz | — | Florida Marlins | Free agent signing |
| Dec 21, 2004 | Signed as free agent | Craig Counsell | — | Arizona Diamondbacks | Free agent signing |
| Dec 21, 2004 | Signed as free agent | Ben Davis | — | Chicago White Sox | Free agent signing |
| Dec 21, 2004 | Signed as free agent | Lenny DiNardo | — | Boston Red Sox | Free agent signing |
| Dec 21, 2004 | Signed as free agent | Wayne Franklin | — | San Francisco Giants | Free agent signing |
| Dec 21, 2004 | Signed as free agent | Geoff Geary | — | Philadelphia Phillies | Free agent signing |
| Dec 21, 2004 | Signed as free agent | Fernando Lunar | — | Cleveland Indians | Free agent signing |
| Dec 21, 2004 | Signed as free agent | Greg Norton | — | Colorado Rockies | Free agent signing |
| Dec 21, 2004 | Signed as free agent | Chad Paronto | — | Milwaukee Brewers | Free agent signing |
| Dec 21, 2004 | Signed as free agent | Joe Randa | — | Cincinnati Reds | Free agent signing |
| Dec 21, 2004 | Signed as free agent | Chris Saenz | — | Milwaukee Brewers | Free agent signing |
| Dec 21, 2004 | Signed as free agent | Pat Strange | — | Minnesota Twins | Free agent signing |
| Dec 21, 2004 | Signed as free agent | Amaury Telemaco | — | Philadelphia Phillies | Free agent signing |
| Dec 21, 2004 | Signed as free agent | Jose Valentin | — | Los Angeles Dodgers | Free agent signing |
| Dec 20, 2004 | Signed as free agent | Antonio Alfonseca | — | Florida Marlins | Free agent signing |
| Dec 20, 2004 | Signed as free agent | Nate Bland | — | Seattle Mariners | Free agent signing |
| Dec 20, 2004 | Signed as free agent | Travis Chapman | — | Cincinnati Reds | Free agent signing |
| Dec 20, 2004 | Signed as free agent | Greg Colbrunn | — | Texas Rangers | Free agent signing |
| Dec 20, 2004 | Signed as free agent | David Dellucci | — | Texas Rangers | Free agent signing |
| Dec 20, 2004 | Signed as free agent | Gene Kingsale | — | Baltimore Orioles | Free agent signing |
| Dec 20, 2004 | Signed as free agent | Steve Kline | — | Baltimore Orioles | Free agent signing |
| Dec 20, 2004 | Signed as free agent | Kent Mercker | — | Cincinnati Reds | Free agent signing |
| Dec 20, 2004 | Signed as free agent | Danny Patterson | — | San Diego Padres | Free agent signing |
| Dec 20, 2004 | Signed as free agent | Carl Pavano | — | New York Yankees | Free agent signing |
| Dec 20, 2004 | Released | Tony Saunders | Tampa Bay Devil Rays | — | Release |
| Dec 20, 2004 | Signed as free agent | Russ Springer | — | Houston Astros | Free agent signing |
| Dec 20, 2004 | Signed as free agent | Tony Womack | — | New York Yankees | Free agent signing |
| Dec 20, 2004 | Trade | Unnamed | San Diego Padres | Boston Red Sox | $ |
| Dec 20, 2004 | Trade | Jay Payton | San Diego Padres | Boston Red Sox | Trade |
| Dec 20, 2004 | Trade | Ramon Vazquez | San Diego Padres | Boston Red Sox | Trade |
| Dec 20, 2004 | Trade | David Pauley | San Diego Padres | Boston Red Sox | Trade |
| Dec 20, 2004 | Trade | Dave Roberts | Boston Red Sox | San Diego Padres | Trade |
| Dec 20, 2004 | Trade | Sean Green | Colorado Rockies | Seattle Mariners | Trade |
| Dec 20, 2004 | Trade | Aaron Taylor | Seattle Mariners | Colorado Rockies | Trade |
| Dec 19, 2004 | Signed as free agent | Jason Christiansen | — | San Francisco Giants | Free agent signing |
| Dec 19, 2004 | Signed as free agent | Placido Polanco | — | Philadelphia Phillies | Free agent signing |
| Dec 19, 2004 | Signed as free agent | Edgar Renteria | — | Boston Red Sox | Free agent signing |
| Dec 19, 2004 | Signed as free agent | Ron Villone | — | Seattle Mariners | Free agent signing |
| Dec 18, 2004 | Signed as free agent | Danny Ardoin | — | Colorado Rockies | Free agent signing |
| Dec 18, 2004 | Released | Dane De La Rosa | New York Yankees | — | Release |
| Dec 18, 2004 | Signed as free agent | Tim Olson | — | Colorado Rockies | Free agent signing |
| Dec 18, 2004 | Signed as free agent | Chad Zerbe | — | Cleveland Indians | Free agent signing |
| Dec 18, 2004 | Trade | Dan Haren | St. Louis Cardinals | Oakland Athletics | Trade |
| Dec 18, 2004 | Trade | Kiko Calero | St. Louis Cardinals | Oakland Athletics | Trade |
| Dec 18, 2004 | Trade | Daric Barton | St. Louis Cardinals | Oakland Athletics | Trade |
| Dec 18, 2004 | Trade | Mark Mulder | Oakland Athletics | St. Louis Cardinals | Trade |
| Dec 17, 2004 | Signed as free agent | Adrian Beltre | — | Seattle Mariners | Free agent signing |
| Dec 17, 2004 | Signed as free agent | Brian Buchanan | — | Tampa Bay Devil Rays | Free agent signing |
| Dec 17, 2004 | Signed as free agent | John Halama | — | Boston Red Sox | Free agent signing |
| Dec 17, 2004 | Signed as free agent | Luis Jimenez | — | Minnesota Twins | Free agent signing |
| Dec 17, 2004 | Signed as free agent | Brandon Larson | — | Tampa Bay Devil Rays | Free agent signing |
| Dec 17, 2004 | Signed as free agent | Brian Mallette | — | Pittsburgh Pirates | Free agent signing |
| Dec 17, 2004 | Signed as free agent | Pedro Martinez | — | New York Mets | Free agent signing |
| Dec 17, 2004 | Signed as free agent | Denny Stark | — | Cleveland Indians | Free agent signing |
| Dec 17, 2004 | Signed as free agent | David Wells | — | Boston Red Sox | Free agent signing |
| Dec 16, 2004 | Signed as free agent | Eliezer Alfonzo | — | San Francisco Giants | Free agent signing |
| Dec 16, 2004 | Signed as free agent | Napoleon Calzado | — | Baltimore Orioles | Free agent signing |
| Dec 16, 2004 | Signed as free agent | Royce Clayton | — | Arizona Diamondbacks | Free agent signing |
| Dec 16, 2004 | Signed as free agent | Wilson Delgado | — | Florida Marlins | Free agent signing |
| Dec 16, 2004 | Signed as free agent | Scott Downs | — | Toronto Blue Jays | Free agent signing |
| Dec 16, 2004 | Signed as free agent | Sal Fasano | — | Baltimore Orioles | Free agent signing |
| Dec 16, 2004 | Signed as free agent | Jared Fernandez | — | Cincinnati Reds | Free agent signing |
| Dec 16, 2004 | Released | Steve Green | Anaheim Angels | — | Release |
| Dec 16, 2004 | Signed as free agent | Trey Hodges | — | Minnesota Twins | Free agent signing |
| Dec 16, 2004 | Signed as free agent | Kevin McGlinchy | — | Chicago Cubs | Free agent signing |
| Dec 16, 2004 | Signed as free agent | Brian McNichol | — | Baltimore Orioles | Free agent signing |
| Dec 16, 2004 | Released | Damon Minor | Pittsburgh Pirates | — | Release |
| Dec 16, 2004 | Signed as free agent | Bry Nelson | — | Toronto Blue Jays | Free agent signing |
| Dec 16, 2004 | Released | A. J. Pierzynski | San Francisco Giants | — | Release |
| Dec 16, 2004 | Trade | Keith Ginter | Milwaukee Brewers | Oakland Athletics | Trade |
| Dec 16, 2004 | Trade | Justin Lehr | Oakland Athletics | Milwaukee Brewers | Trade |
| Dec 16, 2004 | Trade | Nelson Cruz | Oakland Athletics | Milwaukee Brewers | Trade |
| Dec 16, 2004 | Trade | Unnamed | Kansas City Royals | Pittsburgh Pirates | $ |
| Dec 16, 2004 | Trade | Benito Santiago | Kansas City Royals | Pittsburgh Pirates | Trade |
| Dec 16, 2004 | Trade | Juan Carlos Oviedo | Pittsburgh Pirates | Kansas City Royals | Trade |
| Dec 16, 2004 | Trade | Unnamed | Atlanta Braves | Kansas City Royals | $ |
| Dec 16, 2004 | Trade | Eli Marrero | Atlanta Braves | Kansas City Royals | Trade |
| Dec 16, 2004 | Trade | Jorge Vasquez | Kansas City Royals | Atlanta Braves | Trade |
| Dec 16, 2004 | Trade | Juan Cruz | Atlanta Braves | Oakland Athletics | Trade |
| Dec 16, 2004 | Trade | Dan Meyer | Atlanta Braves | Oakland Athletics | Trade |
| Dec 16, 2004 | Trade | Charles Thomas | Atlanta Braves | Oakland Athletics | Trade |
| Dec 16, 2004 | Trade | Tim Hudson | Oakland Athletics | Atlanta Braves | Trade |
| Dec 15, 2004 | Signed as free agent | Jeff Bailey | — | Boston Red Sox | Free agent signing |
| Dec 15, 2004 | Released | Chad Bentz | Washington Nationals | — | Release |
| Dec 15, 2004 | Signed as free agent | Emil Brown | — | Kansas City Royals | Free agent signing |
| Dec 15, 2004 | Released | Mike Bynum | San Diego Padres | — | Release |
| Dec 15, 2004 | Signed as free agent | Ramon Castro | — | New York Mets | Free agent signing |
| Dec 15, 2004 | Signed as free agent | Jeff Fassero | — | San Francisco Giants | Free agent signing |
| Dec 15, 2004 | Released | Andrew Good | Arizona Diamondbacks | — | Release |
| Dec 15, 2004 | Signed as free agent | Jose Hernandez | — | Cleveland Indians | Free agent signing |
| Dec 15, 2004 | Signed as free agent | Jeff Kent | — | Los Angeles Dodgers | Free agent signing |
| Dec 15, 2004 | Signed as free agent | Tim Laker | — | Tampa Bay Devil Rays | Free agent signing |
| Dec 15, 2004 | Signed as free agent | Mike Matheny | — | San Francisco Giants | Free agent signing |
| Dec 15, 2004 | Signed as free agent | Terry Mulholland | — | Minnesota Twins | Free agent signing |
| Dec 15, 2004 | Signed as free agent | Kevin Orie | — | Milwaukee Brewers | Free agent signing |
| Dec 15, 2004 | Signed as free agent | Tommy Phelps | — | Milwaukee Brewers | Free agent signing |
| Dec 15, 2004 | Signed as free agent | Jason Phillips | — | Tampa Bay Devil Rays | Free agent signing |
| Dec 15, 2004 | Signed as free agent | Simon Pond | — | Boston Red Sox | Free agent signing |
| Dec 15, 2004 | Signed as free agent | Brandon Puffer | — | San Francisco Giants | Free agent signing |
| Dec 15, 2004 | Signed as free agent | Alex Serrano | — | Colorado Rockies | Free agent signing |
| Dec 15, 2004 | Signed as free agent | Richie Sexson | — | Seattle Mariners | Free agent signing |
| Dec 15, 2004 | Signed as free agent | Kelly Stinnett | — | Arizona Diamondbacks | Free agent signing |
| Dec 15, 2004 | Signed as free agent | Andy Tracy | — | Colorado Rockies | Free agent signing |
| Dec 15, 2004 | Signed as free agent | David Weathers | — | Cincinnati Reds | Free agent signing |
| Dec 15, 2004 | Signed as free agent | Ben Weber | — | Cincinnati Reds | Free agent signing |
| Dec 15, 2004 | Released | Dan Wright | Chicago White Sox | — | Release |
| Dec 14, 2004 | Signed as free agent | Jimmy Anderson | — | Chicago Cubs | Free agent signing |
| Dec 14, 2004 | Signed as free agent | Paul Byrd | — | Anaheim Angels | Free agent signing |
| Dec 14, 2004 | Signed as free agent | Einar Diaz | — | St. Louis Cardinals | Free agent signing |
| Dec 14, 2004 | Signed as free agent | Angel Echevarria | — | Chicago Cubs | Free agent signing |
| Dec 14, 2004 | Signed as free agent | Brian Gordon | — | Anaheim Angels | Free agent signing |
| Dec 14, 2004 | Signed as free agent | Delvin James | — | Anaheim Angels | Free agent signing |
| Dec 14, 2004 | Signed as free agent | Todd Jones | — | Florida Marlins | Free agent signing |
| Dec 14, 2004 | Signed as free agent | Danny Klassen | — | Chicago Cubs | Free agent signing |
| Dec 14, 2004 | Signed as free agent | Corey Koskie | — | Toronto Blue Jays | Free agent signing |
| Dec 14, 2004 | Signed as free agent | Mickey Lopez | — | Seattle Mariners | Free agent signing |
| Dec 14, 2004 | Signed as free agent | Billy McMillon | — | Boston Red Sox | Free agent signing |
| Dec 14, 2004 | Signed as free agent | Jose Mercedes | — | Chicago Cubs | Free agent signing |
| Dec 14, 2004 | Signed as free agent | Brian Moehler | — | Florida Marlins | Free agent signing |
| Dec 14, 2004 | Signed as free agent | Calvin Murray | — | Chicago Cubs | Free agent signing |
| Dec 14, 2004 | Signed as free agent | Chris Prieto | — | Anaheim Angels | Free agent signing |
| Dec 14, 2004 | Signed as free agent | Bud Smith | — | Minnesota Twins | Free agent signing |
| Dec 14, 2004 | Signed as free agent | Glenn Williams | — | Minnesota Twins | Free agent signing |
| Dec 14, 2004 | Signed as free agent | Esteban Yan | — | Anaheim Angels | Free agent signing |
| Dec 14, 2004 | Trade | Tom Mastny | Toronto Blue Jays | Cleveland Indians | Trade |
| Dec 14, 2004 | Trade | Alec Zumwalt | Atlanta Braves | Milwaukee Brewers | Trade |
| Dec 14, 2004 | Trade | Dustin Moseley | Cincinnati Reds | Anaheim Angels | Trade |
| Dec 14, 2004 | Trade | Ramon Ortiz | Anaheim Angels | Cincinnati Reds | Trade |
| Dec 13, 2004 | Signed as free agent | Roger Clemens | — | Houston Astros | Free agent signing |
| Dec 13, 2004 | Signed as free agent | Wil Cordero | — | Washington Nationals | Free agent signing |
| Dec 13, 2004 | Signed | Miguel Gonzalez | — | Anaheim Angels | Amateur free agent signing |
| Dec 13, 2004 | Signed as free agent | Jeffrey Hammonds | — | Washington Nationals | Free agent signing |
| Dec 13, 2004 | Signed as free agent | Julio Ramirez | — | San Francisco Giants | Free agent signing |
| Dec 13, 2004 | Trade | Scott Podsednik | Milwaukee Brewers | Chicago White Sox | Trade |
| Dec 13, 2004 | Trade | Luis Vizcaino | Milwaukee Brewers | Chicago White Sox | Trade |
| Dec 13, 2004 | Trade | Carlos Lee | Chicago White Sox | Milwaukee Brewers | Trade |
| Dec 13, 2004 | Signed | Yohan Flande | — | Philadelphia Phillies | Amateur free agent signing |
| Dec 12, 2004 | Signed as free agent | Richard Hidalgo | — | Texas Rangers | Free agent signing |
| Dec 12, 2004 | Trade | Chad Gaudin | Tampa Bay Devil Rays | Toronto Blue Jays | Trade |
| Dec 12, 2004 | Trade | Kevin Cash | Toronto Blue Jays | Tampa Bay Devil Rays | Trade |
| Dec 11, 2004 | Signed as free agent | Steve Finley | — | Anaheim Angels | Free agent signing |
| Dec 11, 2004 | Signed as free agent | Troy Glaus | — | Arizona Diamondbacks | Free agent signing |
| Dec 11, 2004 | Signed as free agent | Russ Ortiz | — | Arizona Diamondbacks | Free agent signing |
| Dec 11, 2004 | Signed as free agent | Kelly Wunsch | — | Los Angeles Dodgers | Free agent signing |
| Dec 11, 2004 | Trade | Arthur Rhodes | Pittsburgh Pirates | Cleveland Indians | Trade |
| Dec 11, 2004 | Trade | Matt Lawton | Cleveland Indians | Pittsburgh Pirates | Trade |
| Dec 11, 2004 | Trade | Danny Kolb | Milwaukee Brewers | Atlanta Braves | Trade |
| Dec 11, 2004 | Trade | Jose Capellan | Atlanta Braves | Milwaukee Brewers | Trade |
| Dec 10, 2004 | Released | Val Pascucci | Washington Nationals | — | Release |
| Dec 9, 2004 | Signed as free agent | Geoff Blum | — | San Diego Padres | Free agent signing |
| Dec 9, 2004 | Signed as free agent | Jermaine Dye | — | Chicago White Sox | Free agent signing |
| Dec 9, 2004 | Signed as free agent | Julio Franco | — | Atlanta Braves | Free agent signing |
| Dec 9, 2004 | Signed as free agent | Dustin Hermanson | — | Chicago White Sox | Free agent signing |
| Dec 9, 2004 | Signed as free agent | Woody Williams | — | San Diego Padres | Free agent signing |
| Dec 9, 2004 | Signed as free agent | Eric Young | — | San Diego Padres | Free agent signing |
| Dec 8, 2004 | Signed as free agent | Sandy Alomar | — | Texas Rangers | Free agent signing |
| Dec 8, 2004 | Signed as free agent | Henry Blanco | — | Chicago Cubs | Free agent signing |
| Dec 8, 2004 | Signed | Welington Castillo | — | Chicago Cubs | Amateur free agent signing |
| Dec 8, 2004 | Signed as free agent | Elmer Dessens | — | Los Angeles Dodgers | Free agent signing |
| Dec 8, 2004 | Signed as free agent | Chris Gomez | — | Baltimore Orioles | Free agent signing |
| Dec 8, 2004 | Signed as free agent | Al Leiter | — | Florida Marlins | Free agent signing |
| Dec 8, 2004 | Signed as free agent | Jon Lieber | — | Philadelphia Phillies | Free agent signing |
| Dec 8, 2004 | Signed as free agent | Matt Mantei | — | Boston Red Sox | Free agent signing |
| Dec 7, 2004 | Signed as free agent | Kevin Appier | — | Kansas City Royals | Free agent signing |
| Dec 7, 2004 | Signed as free agent | Rheal Cormier | — | Philadelphia Phillies | Free agent signing |
| Dec 7, 2004 | Signed as free agent | Mike DeJean | — | New York Mets | Free agent signing |
| Dec 7, 2004 | Signed as free agent | Cal Eldred | — | St. Louis Cardinals | Free agent signing |
| Dec 7, 2004 | Signed as free agent | Nomar Garciaparra | — | Chicago Cubs | Free agent signing |
| Dec 7, 2004 | Signed as free agent | Jimmy Haynes | — | Tampa Bay Devil Rays | Free agent signing |
| Dec 7, 2004 | Signed as free agent | Ricky Ledee | — | Los Angeles Dodgers | Free agent signing |
| Dec 7, 2004 | Signed as free agent | John Mabry | — | St. Louis Cardinals | Free agent signing |
| Dec 7, 2004 | Signed as free agent | Luis Martinez | — | Arizona Diamondbacks | Free agent signing |
| Dec 7, 2004 | Signed as free agent | Quinton McCracken | — | Arizona Diamondbacks | Free agent signing |
| Dec 7, 2004 | Signed as free agent | Matt Morris | — | St. Louis Cardinals | Free agent signing |
| Dec 7, 2004 | Signed as free agent | Orlando Palmeiro | — | Houston Astros | Free agent signing |
| Dec 7, 2004 | Signed as free agent | Todd Pratt | — | Philadelphia Phillies | Free agent signing |
| Dec 7, 2004 | Signed as free agent | Brad Radke | — | Minnesota Twins | Free agent signing |
| Dec 7, 2004 | Signed as free agent | B. J. Surhoff | — | Baltimore Orioles | Free agent signing |
| Dec 7, 2004 | Signed as free agent | Todd Walker | — | Chicago Cubs | Free agent signing |
| Dec 7, 2004 | Signed as free agent | Dan Wilson | — | Seattle Mariners | Free agent signing |
| Dec 7, 2004 | Signed | Juan Jaime | — | Montreal Expos | Amateur free agent signing |
| Dec 6, 2004 | Signed as free agent | Andy Dominique | — | New York Mets | Free agent signing |
| Dec 6, 2004 | Signed as free agent | John Flaherty | — | New York Yankees | Free agent signing |
| Dec 6, 2004 | Signed as free agent | Jose Vizcaino | — | Houston Astros | Free agent signing |
| Dec 3, 2004 | Signed as free agent | Kane Davis | — | Milwaukee Brewers | Free agent signing |
| Dec 3, 2004 | Signed | Hector Noesi | — | New York Yankees | Amateur free agent signing |
| Dec 3, 2004 | Trade | Mike Stanton | New York Mets | New York Yankees | Trade |
| Dec 3, 2004 | Trade | Felix Heredia | New York Yankees | New York Mets | Trade |
| Dec 3, 2004 | Trade | Felix Rodriguez | Philadelphia Phillies | New York Yankees | Trade |
| Dec 3, 2004 | Trade | Kenny Lofton | New York Yankees | Philadelphia Phillies | Trade |
| Dec 2, 2004 | Signed as free agent | Rigo Beltran | — | Milwaukee Brewers | Free agent signing |
| Dec 2, 2004 | Signed as free agent | Armando Benitez | — | San Francisco Giants | Free agent signing |
| Dec 2, 2004 | Signed as free agent | Peter Bergeron | — | Chicago Cubs | Free agent signing |
| Dec 2, 2004 | Signed as free agent | Trent Durrington | — | Milwaukee Brewers | Free agent signing |
| Dec 2, 2004 | Signed as free agent | Aquilino Lopez | — | Los Angeles Dodgers | Free agent signing |
| Dec 2, 2004 | Trade | John McDonald | Cleveland Indians | Toronto Blue Jays | Trade |
| Dec 1, 2004 | Signed as free agent | Erick Almonte | — | Cleveland Indians | Free agent signing |
| Dec 1, 2004 | Released | Tony Alvarez | Pittsburgh Pirates | — | Release |
| Dec 1, 2004 | Signed as free agent | Esteban German | — | Texas Rangers | Free agent signing |
| Dec 1, 2004 | Signed as free agent | Chris Gissell | — | St. Louis Cardinals | Free agent signing |
| Dec 1, 2004 | Signed as free agent | Alex Herrera | — | Atlanta Braves | Free agent signing |
| Dec 1, 2004 | Released | Abraham Nunez | Pittsburgh Pirates | — | Release |
| Dec 1, 2004 | Released | Carlos Rivera | Pittsburgh Pirates | — | Release |
| Nov 30, 2004 | Signed as free agent | Kris Benson | — | New York Mets | Free agent signing |
| Nov 30, 2004 | Signed as free agent | Mark Corey | — | Pittsburgh Pirates | Free agent signing |
| Nov 30, 2004 | Signed as free agent | Sam McConnell | — | Atlanta Braves | Free agent signing |
| Nov 30, 2004 | Signed as free agent | Damian Miller | — | Milwaukee Brewers | Free agent signing |
| Nov 30, 2004 | Signed as free agent | Paul Wilson | — | Cincinnati Reds | Free agent signing |
| Nov 29, 2004 | Signed as free agent | Gary Bennett | — | Washington Nationals | Free agent signing |
| Nov 29, 2004 | Signed as free agent | Jamie Brown | — | Boston Red Sox | Free agent signing |
| Nov 29, 2004 | Released | Scott Downs | Washington Nationals | — | Release |
| Nov 29, 2004 | Signed as free agent | Lenny Harris | — | Florida Marlins | Free agent signing |
| Nov 29, 2004 | Signed as free agent | Doug Mirabelli | — | Boston Red Sox | Free agent signing |
| Nov 29, 2004 | Signed as free agent | Juan Padilla | — | New York Mets | Free agent signing |
| Nov 29, 2004 | Signed as free agent | Dennys Reyes | — | San Diego Padres | Free agent signing |
| Nov 29, 2004 | Signed as free agent | Michael Tejera | — | Texas Rangers | Free agent signing |
| Nov 27, 2004 | Trade | Unnamed | Pittsburgh Pirates | Oakland Athletics | $ |
| Nov 27, 2004 | Trade | Jason Kendall | Pittsburgh Pirates | Oakland Athletics | Trade |
| Nov 27, 2004 | Trade | Unnamed | Oakland Athletics | Pittsburgh Pirates | $ |
| Nov 27, 2004 | Trade | Mark Redman | Oakland Athletics | Pittsburgh Pirates | Trade |
| Nov 27, 2004 | Trade | Arthur Rhodes | Oakland Athletics | Pittsburgh Pirates | Trade |
| Nov 24, 2004 | Released | Marlon Anderson | St. Louis Cardinals | — | Release |
| Nov 24, 2004 | Signed as free agent | Mike Redmond | — | Minnesota Twins | Free agent signing |
| Nov 24, 2004 | Signed as free agent | Rudy Seanez | — | San Diego Padres | Free agent signing |
| Nov 24, 2004 | Signed as free agent | Bob Wickman | — | Cleveland Indians | Free agent signing |
| Nov 24, 2004 | Trade | J. J. Davis | Pittsburgh Pirates | Washington Nationals | Trade |
| Nov 24, 2004 | Trade | Antonio Sucre | Washington Nationals | Pittsburgh Pirates | Trade |
| Nov 23, 2004 | Released | Geoff Blum | Tampa Bay Devil Rays | — | Release |
| Nov 23, 2004 | Signed as free agent | Juan Castro | — | Minnesota Twins | Free agent signing |
| Nov 23, 2004 | Signed as free agent | Jim Crowell | — | Florida Marlins | Free agent signing |
| Nov 23, 2004 | Released | Geremi Gonzalez | Tampa Bay Devil Rays | — | Release |
| Nov 23, 2004 | Released | Damian Rolls | Tampa Bay Devil Rays | — | Release |
| Nov 23, 2004 | Signed as free agent | Kevin Walker | — | Chicago White Sox | Free agent signing |
| Nov 22, 2004 | Signed as free agent | Mike Bell | — | St. Louis Cardinals | Free agent signing |
| Nov 22, 2004 | Signed as free agent | Hiram Bocachica | — | Oakland Athletics | Free agent signing |
| Nov 22, 2004 | Signed as free agent | Brent Butler | — | Tampa Bay Devil Rays | Free agent signing |
| Nov 22, 2004 | Signed as free agent | Damion Easley | — | Florida Marlins | Free agent signing |
| Nov 22, 2004 | Signed as free agent | Robert Machado | — | Texas Rangers | Free agent signing |
| Nov 22, 2004 | Signed as free agent | Jason Roach | — | Tampa Bay Devil Rays | Free agent signing |
| Nov 22, 2004 | Signed as free agent | Glendon Rusch | — | Chicago Cubs | Free agent signing |
| Nov 19, 2004 | Signed as free agent | Chip Ambres | — | Boston Red Sox | Free agent signing |
| Nov 19, 2004 | Signed as free agent | Brandon Berger | — | St. Louis Cardinals | Free agent signing |
| Nov 19, 2004 | Signed as free agent | Ryan Jensen | — | Kansas City Royals | Free agent signing |
| Nov 19, 2004 | Signed as free agent | Matt Kinney | — | San Francisco Giants | Free agent signing |
| Nov 19, 2004 | Signed as free agent | Mike Mahoney | — | St. Louis Cardinals | Free agent signing |
| Nov 19, 2004 | Signed as free agent | Greg Myers | — | Toronto Blue Jays | Free agent signing |
| Nov 19, 2004 | Signed as free agent | Kevin Pickford | — | San Francisco Giants | Free agent signing |
| Nov 19, 2004 | Signed as free agent | Mike Rose | — | Los Angeles Dodgers | Free agent signing |
| Nov 19, 2004 | Released | Jason Simontacchi | St. Louis Cardinals | — | Release |
| Nov 19, 2004 | Signed as free agent | Earl Snyder | — | Tampa Bay Devil Rays | Free agent signing |
| Nov 19, 2004 | Signed as free agent | Brad Voyles | — | New York Yankees | Free agent signing |
| Nov 19, 2004 | Signed as free agent | Kris Wilson | — | Boston Red Sox | Free agent signing |
| Nov 19, 2004 | Trade | Maicer Izturis | Washington Nationals | Anaheim Angels | Trade |
| Nov 19, 2004 | Trade | Juan Rivera | Washington Nationals | Anaheim Angels | Trade |
| Nov 19, 2004 | Trade | Jose Guillen | Anaheim Angels | Washington Nationals | Trade |
| Nov 19, 2004 | Trade | Randy Williams | Seattle Mariners | San Diego Padres | Trade |
| Nov 19, 2004 | Trade | Billy Hogan | San Diego Padres | Seattle Mariners | Trade |
| Nov 18, 2004 | Signed as free agent | Mike Bacsik | — | Philadelphia Phillies | Free agent signing |
| Nov 18, 2004 | Signed as free agent | Buddy Carlyle | — | Los Angeles Dodgers | Free agent signing |
| Nov 18, 2004 | Signed as free agent | Yamid Haad | — | San Francisco Giants | Free agent signing |
| Nov 18, 2004 | Signed as free agent | Jason Kershner | — | Boston Red Sox | Free agent signing |
| Nov 18, 2004 | Signed as free agent | Jose Leon | — | Pittsburgh Pirates | Free agent signing |
| Nov 18, 2004 | Signed as free agent | Jeff Liefer | — | Cleveland Indians | Free agent signing |
| Nov 18, 2004 | Signed as free agent | Chris Mears | — | Atlanta Braves | Free agent signing |
| Nov 18, 2004 | Signed as free agent | Troy Percival | — | Detroit Tigers | Free agent signing |
| Nov 18, 2004 | Signed as free agent | Colin Porter | — | New York Yankees | Free agent signing |
| Nov 18, 2004 | Signed as free agent | Jimmy Serrano | — | Oakland Athletics | Free agent signing |
| Nov 17, 2004 | Signed as free agent | Jason Alfaro | — | Toronto Blue Jays | Free agent signing |
| Nov 17, 2004 | Signed as free agent | Pat Borders | — | Milwaukee Brewers | Free agent signing |
| Nov 17, 2004 | Signed as free agent | Frank Castillo | — | Florida Marlins | Free agent signing |
| Nov 17, 2004 | Signed as free agent | Bryan Corey | — | Florida Marlins | Free agent signing |
| Nov 17, 2004 | Signed | Kenley Jansen | — | Los Angeles Dodgers | Amateur free agent signing |
| Nov 17, 2004 | Signed as free agent | Russ Johnson | — | New York Yankees | Free agent signing |
| Nov 17, 2004 | Signed as free agent | Cory Lidle | — | Philadelphia Phillies | Free agent signing |
| Nov 17, 2004 | Signed as free agent | Damon Minor | — | Pittsburgh Pirates | Free agent signing |
| Nov 17, 2004 | Signed as free agent | Agustin Montero | — | Texas Rangers | Free agent signing |
| Nov 17, 2004 | Signed as free agent | Joe Roa | — | Pittsburgh Pirates | Free agent signing |
| Nov 16, 2004 | Signed as free agent | Toby Borland | — | St. Louis Cardinals | Free agent signing |
| Nov 16, 2004 | Signed as free agent | Doug Brocail | — | Texas Rangers | Free agent signing |
| Nov 16, 2004 | Signed as free agent | Tim Byrdak | — | Baltimore Orioles | Free agent signing |
| Nov 16, 2004 | Signed as free agent | Vinny Castilla | — | Washington Nationals | Free agent signing |
| Nov 16, 2004 | Signed as free agent | Tony Fiore | — | Baltimore Orioles | Free agent signing |
| Nov 16, 2004 | Signed as free agent | Eddy Garabito | — | Colorado Rockies | Free agent signing |
| Nov 16, 2004 | Signed as free agent | Cristian Guzman | — | Washington Nationals | Free agent signing |
| Nov 16, 2004 | Signed as free agent | Jose Morban | — | Cleveland Indians | Free agent signing |
| Nov 16, 2004 | Signed as free agent | Brian O'Connor | — | Atlanta Braves | Free agent signing |
| Nov 16, 2004 | Signed as free agent | Ken Ray | — | Chicago White Sox | Free agent signing |
| Nov 16, 2004 | Signed as free agent | Saul Rivera | — | Washington Nationals | Free agent signing |
| Nov 16, 2004 | Signed as free agent | John Rodriguez | — | Cleveland Indians | Free agent signing |
| Nov 16, 2004 | Signed as free agent | Anthony Sanders | — | Toronto Blue Jays | Free agent signing |
| Nov 16, 2004 | Signed as free agent | Jason Standridge | — | Texas Rangers | Free agent signing |
| Nov 16, 2004 | Signed as free agent | Andres Torres | — | Texas Rangers | Free agent signing |
| Nov 16, 2004 | Signed as free agent | Omar Vizquel | — | San Francisco Giants | Free agent signing |
| Nov 15, 2004 | Signed as free agent | Andy Abad | — | Cleveland Indians | Free agent signing |
| Nov 15, 2004 | Signed as free agent | Manny Alexander | — | Texas Rangers | Free agent signing |
| Nov 15, 2004 | Signed as free agent | Clay Condrey | — | Philadelphia Phillies | Free agent signing |
| Nov 15, 2004 | Signed as free agent | Brian Cooper | — | San Francisco Giants | Free agent signing |
| Nov 15, 2004 | Signed as free agent | Jack Cust | — | Oakland Athletics | Free agent signing |
| Nov 15, 2004 | Signed as free agent | Robert Ellis | — | Philadelphia Phillies | Free agent signing |
| Nov 15, 2004 | Signed as free agent | A. J. Hinch | — | Philadelphia Phillies | Free agent signing |
| Nov 15, 2004 | Signed as free agent | Kenny Kelly | — | Cincinnati Reds | Free agent signing |
| Nov 15, 2004 | Signed as free agent | Aaron Myette | — | Philadelphia Phillies | Free agent signing |
| Nov 15, 2004 | Signed as free agent | Vladimir Nunez | — | Texas Rangers | Free agent signing |
| Nov 15, 2004 | Signed as free agent | Lou Pote | — | Texas Rangers | Free agent signing |
| Nov 15, 2004 | Signed as free agent | Curtis Pride | — | Anaheim Angels | Free agent signing |
| Nov 15, 2004 | Signed as free agent | Steve Stemle | — | Kansas City Royals | Free agent signing |
| Nov 15, 2004 | Signed as free agent | Jason Tyner | — | Minnesota Twins | Free agent signing |
| Nov 15, 2004 | Signed as free agent | Gil Velazquez | — | Minnesota Twins | Free agent signing |
| Nov 15, 2004 | Signed as free agent | Jose Veras | — | Texas Rangers | Free agent signing |
| Nov 15, 2004 | Signed as free agent | John Wasdin | — | Texas Rangers | Free agent signing |
| Nov 14, 2004 | Signed as free agent | Marino Salas | — | Baltimore Orioles | Free agent signing |
| Nov 12, 2004 | Released | Seth Greisinger | Minnesota Twins | — | Release |
| Nov 12, 2004 | Signed as free agent | Randy Keisler | — | Cincinnati Reds | Free agent signing |
| Nov 12, 2004 | Signed as free agent | Julius Matos | — | Toronto Blue Jays | Free agent signing |
| Nov 12, 2004 | Signed as free agent | Barry Wesson | — | Houston Astros | Free agent signing |
| Nov 11, 2004 | Signed as free agent | Armando Almanza | — | San Francisco Giants | Free agent signing |
| Nov 11, 2004 | Signed as free agent | Jesse Carlson | — | Toronto Blue Jays | Free agent signing |
| Nov 11, 2004 | Signed as free agent | Travis Driskill | — | Houston Astros | Free agent signing |
| Nov 11, 2004 | Signed as free agent | Jesse Garcia | — | San Diego Padres | Free agent signing |
| Nov 11, 2004 | Signed as free agent | Damian Jackson | — | San Diego Padres | Free agent signing |
| Nov 11, 2004 | Signed as free agent | Andrew Lorraine | — | Baltimore Orioles | Free agent signing |
| Nov 11, 2004 | Signed as free agent | Marty McLeary | — | San Diego Padres | Free agent signing |
| Nov 11, 2004 | Signed as free agent | Kit Pellow | — | Seattle Mariners | Free agent signing |
| Nov 11, 2004 | Signed as free agent | Rob Ryan | — | Florida Marlins | Free agent signing |
| Nov 10, 2004 | Released | Rocky Biddle | Washington Nationals | — | Release |
| Nov 10, 2004 | Signed as free agent | Doug Clark | — | San Francisco Giants | Free agent signing |
| Nov 10, 2004 | Signed as free agent | Jason Karnuth | — | Detroit Tigers | Free agent signing |
| Nov 10, 2004 | Signed as free agent | Justin Kaye | — | Pittsburgh Pirates | Free agent signing |
| Nov 10, 2004 | Signed as free agent | Kevin Olsen | — | Pittsburgh Pirates | Free agent signing |
| Nov 10, 2004 | Signed as free agent | Esix Snead | — | Atlanta Braves | Free agent signing |
| Nov 10, 2004 | Signed as free agent | Chris Truby | — | Kansas City Royals | Free agent signing |
| Nov 9, 2004 | Signed as free agent | Sean Douglass | — | Detroit Tigers | Free agent signing |
| Nov 9, 2004 | Signed as free agent | Jeremy Fikac | — | San Francisco Giants | Free agent signing |
| Nov 9, 2004 | Signed as free agent | Mark Johnson | — | Milwaukee Brewers | Free agent signing |
| Nov 9, 2004 | Signed as free agent | Masao Kida | — | Seattle Mariners | Free agent signing |
| Nov 9, 2004 | Signed as free agent | Dave Matranga | — | Anaheim Angels | Free agent signing |
| Nov 9, 2004 | Signed as free agent | Donaldo Mendez | — | San Francisco Giants | Free agent signing |
| Nov 9, 2004 | Signed as free agent | Jeriome Robertson | — | Cincinnati Reds | Free agent signing |
| Nov 9, 2004 | Signed as free agent | Brandon Villafuerte | — | San Francisco Giants | Free agent signing |
| Nov 8, 2004 | Signed as free agent | Josh Hall | — | Cincinnati Reds | Free agent signing |
| Nov 8, 2004 | Signed as free agent | Carlos Maldonado | — | Pittsburgh Pirates | Free agent signing |
| Nov 8, 2004 | Released | Jose Parra | New York Mets | — | Release |
| Nov 8, 2004 | Signed as free agent | Travis Smith | — | Florida Marlins | Free agent signing |
| Nov 8, 2004 | Trade | Unnamed | San Diego Padres | Kansas City Royals | $ |
| Nov 8, 2004 | Trade | Terrence Long | San Diego Padres | Kansas City Royals | Trade |
| Nov 8, 2004 | Trade | Dennis Tankersley | San Diego Padres | Kansas City Royals | Trade |
| Nov 8, 2004 | Trade | Ryan Bukvich | Kansas City Royals | San Diego Padres | Trade |
| Nov 8, 2004 | Trade | Darrell May | Kansas City Royals | San Diego Padres | Trade |
| Nov 6, 2004 | Signed as free agent | Brian Rose | — | Cincinnati Reds | Free agent signing |
| Nov 5, 2004 | Signed as free agent | Joe Beimel | — | Tampa Bay Devil Rays | Free agent signing |
| Nov 5, 2004 | Signed as free agent | Scott Cassidy | — | Boston Red Sox | Free agent signing |
| Nov 5, 2004 | Signed as free agent | Mike Colangelo | — | Florida Marlins | Free agent signing |
| Nov 5, 2004 | Signed as free agent | Mike Coolbaugh | — | Houston Astros | Free agent signing |
| Nov 5, 2004 | Signed as free agent | Mike Edwards | — | Los Angeles Dodgers | Free agent signing |
| Nov 5, 2004 | Signed as free agent | Jose Flores | — | Los Angeles Dodgers | Free agent signing |
| Nov 5, 2004 | Released | Josh Hall | Cincinnati Reds | — | Release |
| Nov 5, 2004 | Signed as free agent | Bart Miadich | — | Florida Marlins | Free agent signing |
| Nov 5, 2004 | Signed as free agent | Brian Reith | — | Pittsburgh Pirates | Free agent signing |
| Nov 5, 2004 | Signed as free agent | Steve Watkins | — | Cleveland Indians | Free agent signing |
| Nov 4, 2004 | Signed as free agent | Ramon Castro | — | Washington Nationals | Free agent signing |
| Nov 4, 2004 | Signed as free agent | Chris Clapinski | — | Kansas City Royals | Free agent signing |
| Nov 4, 2004 | Released | Masao Kida | Seattle Mariners | — | Release |
| Nov 4, 2004 | Signed as free agent | Mark Little | — | Florida Marlins | Free agent signing |
| Nov 3, 2004 | Signed as free agent | Jermaine Clark | — | Oakland Athletics | Free agent signing |
| Nov 3, 2004 | Signed as free agent | John Ennis | — | Detroit Tigers | Free agent signing |
| Nov 3, 2004 | Signed as free agent | Damon Hollins | — | Tampa Bay Devil Rays | Free agent signing |
| Nov 3, 2004 | Signed as free agent | Luis Ordaz | — | Tampa Bay Devil Rays | Free agent signing |
| Nov 3, 2004 | Signed as free agent | Elvis Peña | — | Colorado Rockies | Free agent signing |
| Nov 3, 2004 | Signed as free agent | Tom Shearn | — | Cincinnati Reds | Free agent signing |
| Nov 3, 2004 | Signed as free agent | Matt Whiteside | — | Toronto Blue Jays | Free agent signing |
| Nov 3, 2004 | Signed as free agent | Ernie Young | — | Cleveland Indians | Free agent signing |
| Nov 2, 2004 | Signed as free agent | Seth Etherton | — | Oakland Athletics | Free agent signing |
| Nov 2, 2004 | Signed as free agent | Guillermo Rodriguez | — | San Francisco Giants | Free agent signing |
| Nov 2, 2004 | Signed as free agent | Jorge Velandia | — | Pittsburgh Pirates | Free agent signing |
| Nov 1, 2004 | Signed as free agent | Mark Budzinski | — | Philadelphia Phillies | Free agent signing |
| Nov 1, 2004 | Signed | Jose Ceda | — | San Diego Padres | Amateur free agent signing |
| Nov 1, 2004 | Signed as free agent | Howie Clark | — | Pittsburgh Pirates | Free agent signing |
| Nov 1, 2004 | Signed as free agent | Aaron Holbert | — | Cincinnati Reds | Free agent signing |
| Nov 1, 2004 | Released | Gary Johnson | Anaheim Angels | — | Release |
| Nov 1, 2004 | Signed as free agent | Jon Nunnally | — | Pittsburgh Pirates | Free agent signing |
| Nov 1, 2004 | Signed as free agent | Chris Piersoll | — | Baltimore Orioles | Free agent signing |
| Oct 29, 2004 | Signed as free agent | Chris Coste | — | Philadelphia Phillies | Free agent signing |
| Oct 29, 2004 | Signed as free agent | Craig Dingman | — | Detroit Tigers | Free agent signing |
| Oct 29, 2004 | Signed as free agent | Rene Reyes | — | Chicago Cubs | Free agent signing |
| Oct 29, 2004 | Signed as free agent | Jim Rushford | — | Philadelphia Phillies | Free agent signing |
| Oct 29, 2004 | Signed as free agent | Danny Sandoval | — | Philadelphia Phillies | Free agent signing |
| Oct 29, 2004 | Signed as free agent | Ricky Stone | — | Cincinnati Reds | Free agent signing |
| Oct 28, 2004 | Released | Shane Reynolds | Arizona Diamondbacks | — | Release |
| Oct 28, 2004 | Signed as free agent | Dan Smith | — | Washington Nationals | Free agent signing |
| Oct 28, 2004 | Signed as free agent | Rico Washington | — | Tampa Bay Devil Rays | Free agent signing |
| Oct 27, 2004 | Signed as free agent | Cory Aldridge | — | Kansas City Royals | Free agent signing |
| Oct 27, 2004 | Signed as free agent | Wilkin Ruan | — | Kansas City Royals | Free agent signing |
| Oct 26, 2004 | Signed as free agent | Homer Bush | — | New York Yankees | Free agent signing |
| Oct 26, 2004 | Signed as free agent | Matt Erickson | — | Milwaukee Brewers | Free agent signing |
| Oct 25, 2004 | Signed as free agent | Adrian Brown | — | Kansas City Royals | Free agent signing |
| Oct 25, 2004 | Signed as free agent | Santiago Ramirez | — | Kansas City Royals | Free agent signing |
| Oct 25, 2004 | Signed as free agent | Rick Short | — | Washington Nationals | Free agent signing |
| Oct 21, 2004 | Signed as free agent | Alberto Castillo | — | Kansas City Royals | Free agent signing |
| Oct 20, 2004 | Released | Adam Riggs | Anaheim Angels | — | Release |
| Oct 19, 2004 | Signed as free agent | Juan Brito | — | Arizona Diamondbacks | Free agent signing |
| Oct 18, 2004 | Signed as free agent | James Lofton | — | Baltimore Orioles | Free agent signing |
| Oct 15, 2004 | Signed as free agent | Chad Allen | — | Texas Rangers | Free agent signing |
| Oct 15, 2004 | Released | Midre Cummings | Tampa Bay Devil Rays | — | Release |
| Oct 15, 2004 | Released | Sal Fasano | New York Yankees | — | Release |
| Oct 15, 2004 | Released | Mark Little | Cleveland Indians | — | Release |
| Oct 15, 2004 | Released | Bryan Ward | Seattle Mariners | — | Release |
| Oct 14, 2004 | Released | Nelson Figueroa | Pittsburgh Pirates | — | Release |
| Oct 14, 2004 | Released | Dan Smith | Washington Nationals | — | Release |
| Oct 14, 2004 | Released | Joe Vitiello | Detroit Tigers | — | Release |
| Oct 12, 2004 | Signed as free agent | Phil Seibel | — | Boston Red Sox | Free agent signing |
| Oct 12, 2004 | Released | Joakim Soria | Los Angeles Dodgers | — | Release |
| Oct 11, 2004 | Signed | Joel Carreno | — | Toronto Blue Jays | Amateur free agent signing |
| Oct 11, 2004 | Released | Alfredo Figaro | Los Angeles Dodgers | — | Release |
| Oct 11, 2004 | Signed as free agent | Jason Romano | — | Cincinnati Reds | Free agent signing |
| Oct 8, 2004 | Released | Billy Koch | Florida Marlins | — | Release |
| Oct 7, 2004 | Released | Jay Witasick | San Diego Padres | — | Release |
| Sep 30, 2004 | Signed | Manny Pina | — | Texas Rangers | Amateur free agent signing |
| Sep 29, 2004 | Released | Jeff Fassero | Colorado Rockies | — | Release |
| Sep 29, 2004 | Signed as free agent | Jeff Fassero | — | Arizona Diamondbacks | Free agent signing |
| Sep 28, 2004 | Released | Phil Seibel | Boston Red Sox | — | Release |
| Sep 27, 2004 | Signed | Jhoulys Chacin | — | Colorado Rockies | Amateur free agent signing |
| Sep 26, 2004 | Signed | David Peralta | — | St. Louis Cardinals | Amateur free agent signing |
| Sep 20, 2004 | Released | Chuck Smith | Atlanta Braves | — | Release |
| Sep 17, 2004 | Trade | Josh Hoffpauir | Texas Rangers | New York Mets | Trade |
| Sep 16, 2004 | Released | Lance Davis | New York Yankees | — | Release |
| Sep 16, 2004 | Signed | Elvin Ramirez | — | New York Mets | Amateur free agent signing |
| Sep 14, 2004 | Released | Matt Beech | Cincinnati Reds | — | Release |
| Sep 13, 2004 | Released | Robinson Cancel | Tampa Bay Devil Rays | — | Release |
| Sep 13, 2004 | Released | Eddie Oropesa | San Diego Padres | — | Release |
| Sep 13, 2004 | Released | Bill Pulsipher | Seattle Mariners | — | Release |
| Sep 10, 2004 | Released | Nick Neugebauer | Milwaukee Brewers | — | Release |
| Sep 10, 2004 | Released | Bill Simas | Seattle Mariners | — | Release |
| Sep 10, 2004 | Released | Randall Simon | Tampa Bay Devil Rays | — | Release |
| Sep 9, 2004 | Released | T. J. Mathews | Los Angeles Dodgers | — | Release |
| Sep 8, 2004 | Released | Paul Abbott | Philadelphia Phillies | — | Release |
| Sep 8, 2004 | Released | McKay Christensen | Cincinnati Reds | — | Release |
| Sep 8, 2004 | Signed | Edgmer Escalona | — | Colorado Rockies | Amateur free agent signing |
| Sep 8, 2004 | Signed as free agent | David Weathers | — | Florida Marlins | Free agent signing |
| Sep 7, 2004 | Released | James Lofton | Baltimore Orioles | — | Release |
| Sep 7, 2004 | Released | David Weathers | Houston Astros | — | Release |
| Sep 7, 2004 | Released | Ben Weber | Anaheim Angels | — | Release |
| Sep 5, 2004 | Released | Randy Keisler | New York Mets | — | Release |
| Sep 3, 2004 | Trade | Andy Pratt | Chicago Cubs | Milwaukee Brewers | Trade |
| Sep 2, 2004 | Released | Marvin Benard | Toronto Blue Jays | — | Release |
| Sep 2, 2004 | Released | Michael Jackson | Chicago White Sox | — | Release |
| Sep 2, 2004 | Trade | Dave Burba | Milwaukee Brewers | San Francisco Giants | Trade |
| Sep 2, 2004 | Trade | Josh Habel | San Francisco Giants | Milwaukee Brewers | Trade |
| Sep 1, 2004 | Signed | Alay Soler | — | New York Mets | Amateur free agent signing |
| Aug 31, 2004 | Trade | Pat Borders | Seattle Mariners | Minnesota Twins | Trade |
| Aug 31, 2004 | Trade | B.J. Garbe | Minnesota Twins | Seattle Mariners | Trade |
| Aug 31, 2004 | Trade | Unnamed | Chicago Cubs | Milwaukee Brewers | $ |
| Aug 31, 2004 | Trade | Ben Grieve | Milwaukee Brewers | Chicago Cubs | Trade |
| Aug 30, 2004 | Released | Karim Garcia | Baltimore Orioles | — | Release |
| Aug 30, 2004 | Signed | Gerardo Parra | — | Arizona Diamondbacks | Amateur free agent signing |
| Aug 27, 2004 | Released | Jesse Garcia | Atlanta Braves | — | Release |
| Aug 27, 2004 | Trade | Dan Wheeler | New York Mets | Houston Astros | Trade |
| Aug 27, 2004 | Trade | Adam Seuss | Houston Astros | New York Mets | Trade |
| Aug 25, 2004 | Signed as free agent | Brian Buchanan | — | New York Mets | Free agent signing |
| Aug 25, 2004 | Released | Micah Franklin | Arizona Diamondbacks | — | Release |
| Aug 23, 2004 | Released | Armando Rios | St. Louis Cardinals | — | Release |
| Aug 23, 2004 | Signed | Matt Young | — | Atlanta Braves | Amateur free agent signing |
| Aug 20, 2004 | Signed as free agent | Matt Beech | — | Cincinnati Reds | Free agent signing |
| Aug 20, 2004 | Signed as free agent | Bill Simas | — | Seattle Mariners | Free agent signing |
| Aug 19, 2004 | Released | Rod Beck | San Diego Padres | — | Release |
| Aug 19, 2004 | Signed as free agent | Robert Fick | — | San Diego Padres | Free agent signing |
| Aug 19, 2004 | Signed as free agent | Neifi Perez | — | Chicago Cubs | Free agent signing |
| Aug 19, 2004 | Signed as free agent | Randall Simon | — | Tampa Bay Devil Rays | Free agent signing |
| Aug 19, 2004 | Trade | Elmer Dessens | Arizona Diamondbacks | Los Angeles Dodgers | Trade |
| Aug 19, 2004 | Trade | Jereme Milons | Los Angeles Dodgers | Arizona Diamondbacks | Trade |
| Aug 18, 2004 | Released | Matt Beech | Boston Red Sox | — | Release |
| Aug 18, 2004 | Signed as free agent | Morgan Burkhart | — | Chicago White Sox | Free agent signing |
| Aug 18, 2004 | Released | Robert Fick | Tampa Bay Devil Rays | — | Release |
| Aug 18, 2004 | Signed as free agent | Ken Huckaby | — | Texas Rangers | Free agent signing |
| Aug 18, 2004 | Signed as free agent | Hansel Izquierdo | — | Pittsburgh Pirates | Free agent signing |
| Aug 18, 2004 | Released | Randall Simon | Pittsburgh Pirates | — | Release |
| Aug 17, 2004 | Signed as free agent | Emil Brown | — | Houston Astros | Free agent signing |
| Aug 17, 2004 | Signed as free agent | Paul Hoover | — | Tampa Bay Devil Rays | Free agent signing |
| Aug 17, 2004 | Signed as free agent | Damian Moss | — | Cincinnati Reds | Free agent signing |
| Aug 17, 2004 | Signed as free agent | Danny Patterson | — | St. Louis Cardinals | Free agent signing |
| Aug 17, 2004 | Released | Neifi Perez | San Francisco Giants | — | Release |
| Aug 17, 2004 | Signed as free agent | Shane Spencer | — | New York Yankees | Free agent signing |
| Aug 17, 2004 | Signed as free agent | Steve Woodard | — | St. Louis Cardinals | Free agent signing |
| Aug 17, 2004 | Trade | Tom Wilson | New York Mets | Los Angeles Dodgers | Trade |
| Aug 17, 2004 | Trade | Tony Socarras | Los Angeles Dodgers | New York Mets | Trade |
| Aug 13, 2004 | Signed as free agent | Kevin Hooper | — | Kansas City Royals | Free agent signing |
| Aug 13, 2004 | Released | Hansel Izquierdo | Chicago Cubs | — | Release |
| Aug 13, 2004 | Released | Damian Moss | Tampa Bay Devil Rays | — | Release |
| Aug 13, 2004 | Released | Danny Patterson | Detroit Tigers | — | Release |
| Aug 13, 2004 | Signed | Carlos Santana | — | Los Angeles Dodgers | Amateur free agent signing |
| Aug 13, 2004 | Signed as free agent | Jorge Toca | — | Detroit Tigers | Free agent signing |
| Aug 13, 2004 | Trade | Eric Eckenstahler | Detroit Tigers | Chicago Cubs | Trade |
| Aug 12, 2004 | Signed | Jose Tabata | — | New York Yankees | Amateur free agent signing |
| Aug 11, 2004 | Released | Paul Hoover | Montreal Expos | — | Release |
| Aug 11, 2004 | Released | Corey Thurman | Montreal Expos | — | Release |
| Aug 11, 2004 | Trade | Luis Martinez | St. Louis Cardinals | Colorado Rockies | Trade |
| Aug 11, 2004 | Trade | Chris Narveson | St. Louis Cardinals | Colorado Rockies | Trade |
| Aug 11, 2004 | Trade | Elizardo Ramirez | Philadelphia Phillies | Cincinnati Reds | Trade |
| Aug 10, 2004 | Trade | Mike Venafro | Kansas City Royals | Los Angeles Dodgers | Trade |
| Aug 10, 2004 | Trade | Elvin Nina | Los Angeles Dodgers | Kansas City Royals | Trade |
| Aug 9, 2004 | Released | Steve Woodard | Oakland Athletics | — | Release |
| Aug 9, 2004 | Trade | Cory Lidle | Cincinnati Reds | Philadelphia Phillies | Trade |
| Aug 9, 2004 | Trade | Javon Moran | Philadelphia Phillies | Cincinnati Reds | Trade |
| Aug 9, 2004 | Trade | Joe Wilson | Philadelphia Phillies | Cincinnati Reds | Trade |
| Aug 6, 2004 | Signed as free agent | Jimmy Anderson | — | Chicago Cubs | Free agent signing |
| Aug 6, 2004 | Signed as free agent | Benito Baez | — | Cincinnati Reds | Free agent signing |
| Aug 6, 2004 | Released | Jeff Cirillo | San Diego Padres | — | Release |
| Aug 6, 2004 | Signed | Rafael Dolis | — | Chicago Cubs | Amateur free agent signing |
| Aug 6, 2004 | Signed as free agent | Andres Galarraga | — | Anaheim Angels | Free agent signing |
| Aug 6, 2004 | Released | Kevin Hooper | New York Yankees | — | Release |
| Aug 6, 2004 | Signed as free agent | Luis Ortiz | — | Montreal Expos | Free agent signing |
| Aug 6, 2004 | Released | Shane Spencer | New York Mets | — | Release |
| Aug 6, 2004 | Trade | Larry Walker | Colorado Rockies | St. Louis Cardinals | Trade |
| Aug 6, 2004 | Trade | Jason Burch | St. Louis Cardinals | Colorado Rockies | Trade |
| Aug 5, 2004 | Released | Jorge Toca | Montreal Expos | — | Release |
| Aug 5, 2004 | Trade | Roberto Alomar | Arizona Diamondbacks | Chicago White Sox | Trade |
| Aug 4, 2004 | Signed as free agent | Ever Magallanes | — | Arizona Diamondbacks | Free agent signing |
| Aug 4, 2004 | Released | Raul Mondesi | Anaheim Angels | — | Release |
| Aug 4, 2004 | Released | Chris Stynes | Pittsburgh Pirates | — | Release |
| Aug 4, 2004 | Trade | Eric Crozier | Cleveland Indians | Toronto Blue Jays | Trade |
| Aug 4, 2004 | Trade | Josh Phelps | Toronto Blue Jays | Cleveland Indians | Trade |
| Aug 3, 2004 | Released | Eric Karros | Oakland Athletics | — | Release |
| Aug 3, 2004 | Signed as free agent | John Olerud | — | New York Yankees | Free agent signing |
| Aug 3, 2004 | Trade | Jeriome Robertson | Cleveland Indians | Montreal Expos | Trade |
| Aug 3, 2004 | Trade | Pierre-Luc Marceau | Montreal Expos | Cleveland Indians | Trade |
| Aug 3, 2004 | Signed | Hector Rondon | — | Cleveland Indians | Amateur free agent signing |
| Aug 2, 2004 | Signed as free agent | Darren Bragg | — | Cincinnati Reds | Free agent signing |
| Aug 2, 2004 | Signed as free agent | Dave Elder | — | New York Yankees | Free agent signing |
| Aug 2, 2004 | Signed as free agent | Tom Evans | — | Pittsburgh Pirates | Free agent signing |
| Aug 2, 2004 | Signed as free agent | Benji Gil | — | Detroit Tigers | Free agent signing |
| Aug 2, 2004 | Signed as free agent | Mark Little | — | Cleveland Indians | Free agent signing |
| Aug 2, 2004 | Signed as free agent | Kevin McGlinchy | — | Chicago Cubs | Free agent signing |
| Aug 2, 2004 | Signed as free agent | Chad Meyers | — | Detroit Tigers | Free agent signing |
| Aug 2, 2004 | Signed as free agent | Kevin Orie | — | Houston Astros | Free agent signing |
| Aug 2, 2004 | Signed as free agent | Keith Osik | — | Tampa Bay Devil Rays | Free agent signing |
| Aug 2, 2004 | Signed as free agent | Jason Pearson | — | Florida Marlins | Free agent signing |
| Aug 2, 2004 | Signed as free agent | Jose Rodriguez | — | Florida Marlins | Free agent signing |
| Aug 2, 2004 | Signed as free agent | Jesus Sanchez | — | Toronto Blue Jays | Free agent signing |
| Aug 2, 2004 | Signed as free agent | Jose Silva | — | Arizona Diamondbacks | Free agent signing |
| Aug 2, 2004 | Signed as free agent | Tim Young | — | St. Louis Cardinals | Free agent signing |
| Aug 2, 2004 | Trade | Mauber Lopez | Philadelphia Phillies | San Diego Padres | Trade |
| Aug 1, 2004 | Released | Jimmy Anderson | Boston Red Sox | — | Release |
| Jul 31, 2004 | Trade | Unnamed | New York Yankees | Chicago White Sox | $ |
| Jul 31, 2004 | Trade | Jose Contreras | New York Yankees | Chicago White Sox | Trade |
| Jul 31, 2004 | Trade | Esteban Loaiza | Chicago White Sox | New York Yankees | Trade |
| Jul 31, 2004 | Trade | Tom Martin | Los Angeles Dodgers | Atlanta Braves | Trade |
| Jul 31, 2004 | Trade | Matt Merricks | Atlanta Braves | Los Angeles Dodgers | Trade |
| Jul 31, 2004 | Trade | Abraham Nunez | Florida Marlins | Kansas City Royals | Trade |
| Jul 31, 2004 | Trade | Rudy Seanez | Kansas City Royals | Florida Marlins | Trade |
| Jul 31, 2004 | Trade | Dave Roberts | Los Angeles Dodgers | Boston Red Sox | Trade |
| Jul 31, 2004 | Trade | Henri Stanley | Boston Red Sox | Los Angeles Dodgers | Trade |
| Jul 31, 2004 | Trade | Ismael Valdez | San Diego Padres | Florida Marlins | Trade |
| Jul 31, 2004 | Trade | Travis Chick | Florida Marlins | San Diego Padres | Trade |
| Jul 31, 2004 | Trade | Scott Erickson | New York Mets | Texas Rangers | Trade |
| Jul 31, 2004 | Trade | Steve Finley | Arizona Diamondbacks | Los Angeles Dodgers | Trade |
| Jul 31, 2004 | Trade | Brent Mayne | Arizona Diamondbacks | Los Angeles Dodgers | Trade |
| Jul 31, 2004 | Trade | Koyie Hill | Los Angeles Dodgers | Arizona Diamondbacks | Trade |
| Jul 31, 2004 | Trade | Bill Murphy | Los Angeles Dodgers | Arizona Diamondbacks | Trade |
| Jul 31, 2004 | Trade | Reggie Abercrombie | Los Angeles Dodgers | Arizona Diamondbacks | Trade |
| Jul 31, 2004 | Trade | Nomar Garciaparra | Boston Red Sox | Chicago Cubs | Trade |
| Jul 31, 2004 | Trade | Matt Murton | Boston Red Sox | Chicago Cubs | Trade |
| Jul 31, 2004 | Trade | Brendan Harris | Chicago Cubs | Montreal Expos | Trade |
| Jul 31, 2004 | Trade | Alex Gonzalez | Chicago Cubs | Montreal Expos | Trade |
| Jul 31, 2004 | Trade | Francis Beltran | Chicago Cubs | Montreal Expos | Trade |
| Jul 31, 2004 | Trade | Orlando Cabrera | Montreal Expos | Boston Red Sox | Trade |
| Jul 31, 2004 | Trade | Doug Mientkiewicz | Minnesota Twins | Boston Red Sox | Trade |
| Jul 31, 2004 | Trade | Justin Jones | Chicago Cubs | Minnesota Twins | Trade |
| Jul 30, 2004 | Signed as free agent | Greg Hansell | — | Arizona Diamondbacks | Free agent signing |
| Jul 30, 2004 | Signed as free agent | Denny Hocking | — | Chicago Cubs | Free agent signing |
| Jul 30, 2004 | Released | Mark Little | Cleveland Indians | — | Release |
| Jul 30, 2004 | Signed as free agent | Jason Tyner | — | Cleveland Indians | Free agent signing |
| Jul 30, 2004 | Trade | Jose Bautista | Kansas City Royals | New York Mets | Trade |
| Jul 30, 2004 | Trade | Justin Huber | New York Mets | Kansas City Royals | Trade |
| Jul 30, 2004 | Trade | Ricky Ledee | Philadelphia Phillies | San Francisco Giants | Trade |
| Jul 30, 2004 | Trade | Alfredo Simon | Philadelphia Phillies | San Francisco Giants | Trade |
| Jul 30, 2004 | Trade | Felix Rodriguez | San Francisco Giants | Philadelphia Phillies | Trade |
| Jul 30, 2004 | Trade | Dave Hansen | Seattle Mariners | San Diego Padres | Trade |
| Jul 30, 2004 | Trade | Jon Huber | San Diego Padres | Seattle Mariners | Trade |
| Jul 30, 2004 | Trade | Josh Hancock | Philadelphia Phillies | Cincinnati Reds | Trade |
| Jul 30, 2004 | Trade | Anderson Machado | Philadelphia Phillies | Cincinnati Reds | Trade |
| Jul 30, 2004 | Trade | Todd Jones | Cincinnati Reds | Philadelphia Phillies | Trade |
| Jul 30, 2004 | Trade | Brad Correll | Cincinnati Reds | Philadelphia Phillies | Trade |
| Jul 30, 2004 | Trade | Paul Lo Duca | Los Angeles Dodgers | Florida Marlins | Trade |
| Jul 30, 2004 | Trade | Guillermo Mota | Los Angeles Dodgers | Florida Marlins | Trade |
| Jul 30, 2004 | Trade | Juan Encarnacion | Los Angeles Dodgers | Florida Marlins | Trade |
| Jul 30, 2004 | Trade | Hee-Seop Choi | Florida Marlins | Los Angeles Dodgers | Trade |
| Jul 30, 2004 | Trade | Brad Penny | Florida Marlins | Los Angeles Dodgers | Trade |
| Jul 30, 2004 | Trade | Bill Murphy | Florida Marlins | Los Angeles Dodgers | Trade |
| Jul 30, 2004 | Trade | Bartolome Fortunato | Tampa Bay Devil Rays | New York Mets | Trade |
| Jul 30, 2004 | Trade | Victor Zambrano | Tampa Bay Devil Rays | New York Mets | Trade |
| Jul 30, 2004 | Trade | Scott Kazmir | New York Mets | Tampa Bay Devil Rays | Trade |
| Jul 30, 2004 | Trade | Jose Diaz | New York Mets | Tampa Bay Devil Rays | Trade |
| Jul 30, 2004 | Trade | Jose Bautista | New York Mets | Pittsburgh Pirates | Trade |
| Jul 30, 2004 | Trade | Ty Wigginton | New York Mets | Pittsburgh Pirates | Trade |
| Jul 30, 2004 | Trade | Matt Peterson | New York Mets | Pittsburgh Pirates | Trade |
| Jul 30, 2004 | Trade | Kris Benson | Pittsburgh Pirates | New York Mets | Trade |
| Jul 30, 2004 | Trade | Jeff Keppinger | Pittsburgh Pirates | New York Mets | Trade |
| Jul 29, 2004 | Released | Nick Bierbrodt | Texas Rangers | — | Release |
| Jul 29, 2004 | Signed | Hector Gomez | — | Colorado Rockies | Amateur free agent signing |
| Jul 29, 2004 | Released | Turk Wendell | Colorado Rockies | — | Release |
| Jul 28, 2004 | Released | Fred McGriff | Tampa Bay Devil Rays | — | Release |
| Jul 28, 2004 | Released | Luis Ortiz | St. Louis Cardinals | — | Release |
| Jul 27, 2004 | Released | John Olerud | Seattle Mariners | — | Release |
| Jul 25, 2004 | Released | Wilfredo Rodriguez | Montreal Expos | — | Release |
| Jul 25, 2004 | Released | Jason Tyner | Atlanta Braves | — | Release |
| Jul 24, 2004 | Trade | Terry Adams | Toronto Blue Jays | Boston Red Sox | Trade |
| Jul 24, 2004 | Trade | John Hattig | Boston Red Sox | Toronto Blue Jays | Trade |
| Jul 23, 2004 | Trade | Rick Short | Kansas City Royals | Montreal Expos | Trade |
| Jul 23, 2004 | Trade | Scott Randall | Montreal Expos | Kansas City Royals | Trade |
| Jul 22, 2004 | Signed as free agent | Hector Almonte | — | Colorado Rockies | Free agent signing |
| Jul 22, 2004 | Signed as free agent | Donzell McDonald | — | New York Yankees | Free agent signing |
| Jul 22, 2004 | Signed as free agent | Matt Skrmetta | — | Montreal Expos | Free agent signing |
| Jul 22, 2004 | Signed as free agent | Corey Thurman | — | Montreal Expos | Free agent signing |
| Jul 22, 2004 | Signed as free agent | Jamey Wright | — | Colorado Rockies | Free agent signing |
| Jul 21, 2004 | Signed as free agent | Brian Bowles | — | Colorado Rockies | Free agent signing |
| Jul 21, 2004 | Released | Felix Martinez | Chicago Cubs | — | Release |
| Jul 21, 2004 | Released | Jamey Wright | Kansas City Royals | — | Release |
| Jul 20, 2004 | Signed as free agent | Pat Mahomes | — | Pittsburgh Pirates | Free agent signing |
| Jul 20, 2004 | Released | Donnie Sadler | Chicago White Sox | — | Release |
| Jul 19, 2004 | Signed as free agent | Andy Fox | — | Texas Rangers | Free agent signing |
| Jul 19, 2004 | Released | Benji Gil | Chicago Cubs | — | Release |
| Jul 19, 2004 | Signed as free agent | C. J. Nitkowski | — | New York Yankees | Free agent signing |
| Jul 19, 2004 | Signed as free agent | Scott Randall | — | Montreal Expos | Free agent signing |
| Jul 19, 2004 | Signed as free agent | Rob Ryan | — | Florida Marlins | Free agent signing |
| Jul 19, 2004 | Trade | Karim Garcia | New York Mets | Baltimore Orioles | Trade |
| Jul 19, 2004 | Trade | Mike DeJean | Baltimore Orioles | New York Mets | Trade |
| Jul 18, 2004 | Released | Hector Almonte | Pittsburgh Pirates | — | Release |
| Jul 18, 2004 | Released | Kris Keller | Texas Rangers | — | Release |
| Jul 18, 2004 | Trade | Carl Everett | Montreal Expos | Chicago White Sox | Trade |
| Jul 18, 2004 | Trade | Gary Majewski | Chicago White Sox | Montreal Expos | Trade |
| Jul 18, 2004 | Trade | Jon Rauch | Chicago White Sox | Montreal Expos | Trade |
| Jul 16, 2004 | Signed as free agent | Kevin Jarvis | — | Pittsburgh Pirates | Free agent signing |
| Jul 16, 2004 | Signed as free agent | Julio Mosquera | — | Texas Rangers | Free agent signing |
| Jul 15, 2004 | Signed as free agent | Vic Darensbourg | — | New York Mets | Free agent signing |
| Jul 15, 2004 | Signed as free agent | Gary Glover | — | Milwaukee Brewers | Free agent signing |
| Jul 15, 2004 | Released | Rick Helling | Texas Rangers | — | Release |
| Jul 15, 2004 | Signed | Ivan Nova | — | New York Yankees | Amateur free agent signing |
| Jul 15, 2004 | Released | Keith Osik | Florida Marlins | — | Release |
| Jul 15, 2004 | Released | Jason Pearson | St. Louis Cardinals | — | Release |
| Jul 15, 2004 | Released | Mike Porzio | Cleveland Indians | — | Release |
| Jul 15, 2004 | Released | Brian Simmons | Minnesota Twins | — | Release |
| Jul 14, 2004 | Signed as free agent | Pedro Astacio | — | Boston Red Sox | Free agent signing |
| Jul 14, 2004 | Signed as free agent | Tony Fiore | — | Baltimore Orioles | Free agent signing |
| Jul 14, 2004 | Released | Andy Fox | Montreal Expos | — | Release |
| Jul 14, 2004 | Released | Mark Lukasiewicz | Toronto Blue Jays | — | Release |
| Jul 14, 2004 | Signed | Jordan Norberto | — | Arizona Diamondbacks | Amateur free agent signing |
| Jul 14, 2004 | Signed as free agent | Cory Vance | — | Texas Rangers | Free agent signing |
| Jul 13, 2004 | Signed as free agent | Derrick Gibson | — | Anaheim Angels | Free agent signing |
| Jul 13, 2004 | Released | Mike Gulan | Chicago White Sox | — | Release |
| Jul 13, 2004 | Released | Jose Rodriguez | Baltimore Orioles | — | Release |
| Jul 12, 2004 | Released | Scott Forster | Florida Marlins | — | Release |
| Jul 12, 2004 | Released | Denny Hocking | Colorado Rockies | — | Release |
| Jul 9, 2004 | Released | Mendy Lopez | Kansas City Royals | — | Release |
| Jul 9, 2004 | Signed as free agent | Reggie Taylor | — | Chicago White Sox | Free agent signing |
| Jul 9, 2004 | Released | Corey Thurman | Cincinnati Reds | — | Release |
| Jul 8, 2004 | Released | Brian Bowles | Milwaukee Brewers | — | Release |
| Jul 8, 2004 | Released | Pat Mahomes | Florida Marlins | — | Release |
| Jul 8, 2004 | Released | Kevin Orie | Cleveland Indians | — | Release |
| Jul 7, 2004 | Signed | Wilson Ramos | — | Minnesota Twins | Amateur free agent signing |
| Jul 6, 2004 | Released | Craig Breslow | Milwaukee Brewers | — | Release |
| Jul 6, 2004 | Released | Kevin Jarvis | Colorado Rockies | — | Release |
| Jul 6, 2004 | Signed as free agent | Armando Rios | — | Baltimore Orioles | Free agent signing |
| Jul 5, 2004 | Signed as free agent | Rodney Myers | — | New York Mets | Free agent signing |
| Jul 5, 2004 | Signed as free agent | Luis Pineda | — | New York Mets | Free agent signing |
| Jul 4, 2004 | Signed as free agent | Darren Bragg | — | San Diego Padres | Free agent signing |
| Jul 4, 2004 | Released | Donovan Osborne | San Diego Padres | — | Release |
| Jul 3, 2004 | Released | Scott Randall | Cincinnati Reds | — | Release |
| Jul 2, 2004 | Released | Darren Bragg | New York Yankees | — | Release |
| Jul 2, 2004 | Signed | Sandy Rosario | — | Florida Marlins | Amateur free agent signing |
| Jul 2, 2004 | Signed as free agent | Wilkin Ruan | — | Kansas City Royals | Free agent signing |
| Jul 2, 2004 | Trade | Jimmy Anderson | Chicago Cubs | Boston Red Sox | Trade |
| Jul 2, 2004 | Trade | Andy Shipman | Boston Red Sox | Chicago Cubs | Trade |
| Jul 1, 2004 | Released | Vic Darensbourg | Chicago White Sox | — | Release |
| Jul 1, 2004 | Released | Gary Glover | Minnesota Twins | — | Release |
| Jul 1, 2004 | Released | Dave Veres | San Francisco Giants | — | Release |
| Jun 30, 2004 | Released | Jeff D'Amico | Cleveland Indians | — | Release |
| Jun 30, 2004 | Signed as free agent | Hansel Izquierdo | — | Chicago Cubs | Free agent signing |
| Jun 30, 2004 | Signed as free agent | Bart Miadich | — | Texas Rangers | Free agent signing |
| Jun 30, 2004 | Signed as free agent | Jose Nunez | — | New York Mets | Free agent signing |
| Jun 30, 2004 | Released | Reggie Taylor | Cincinnati Reds | — | Release |
| Jun 30, 2004 | Released | Cory Vance | Texas Rangers | — | Release |
| Jun 29, 2004 | Released | Trey Hodges | Atlanta Braves | — | Release |
| Jun 29, 2004 | Released | C. J. Nitkowski | Atlanta Braves | — | Release |
| Jun 29, 2004 | Signed as free agent | Scott Sheldon | — | Pittsburgh Pirates | Free agent signing |
| Jun 29, 2004 | Signed as free agent | Russ Springer | — | Houston Astros | Free agent signing |
| Jun 29, 2004 | Released | Mark Watson | Cincinnati Reds | — | Release |
| Jun 28, 2004 | Released | Rodney Myers | Los Angeles Dodgers | — | Release |
| Jun 27, 2004 | Trade | Jeremy Reed | Chicago White Sox | Seattle Mariners | Trade |
| Jun 27, 2004 | Trade | Miguel Olivo | Chicago White Sox | Seattle Mariners | Trade |
| Jun 27, 2004 | Trade | Mike Morse | Chicago White Sox | Seattle Mariners | Trade |
| Jun 27, 2004 | Trade | Freddy Garcia | Seattle Mariners | Chicago White Sox | Trade |
| Jun 27, 2004 | Trade | Ben Davis | Seattle Mariners | Chicago White Sox | Trade |
| Jun 26, 2004 | Signed as free agent | Aaron Boone | — | Cleveland Indians | Free agent signing |
| Jun 26, 2004 | Signed as free agent | Greg Halman | — | Seattle Mariners | Free agent signing |
| Jun 26, 2004 | Released | David Manning | Chicago Cubs | — | Release |
| Jun 26, 2004 | Released | Scott Wiggins | New York Yankees | — | Release |
| Jun 25, 2004 | Released | Justin Kaye | New York Yankees | — | Release |
| Jun 25, 2004 | Released | Bart Miadich | San Diego Padres | — | Release |
| Jun 25, 2004 | Signed as free agent | Joe Winkelsas | — | Chicago White Sox | Free agent signing |
| Jun 24, 2004 | Released | Tony Fiore | Houston Astros | — | Release |
| Jun 24, 2004 | Signed as free agent | Steve Smyth | — | Oakland Athletics | Free agent signing |
| Jun 24, 2004 | Trade | Unnamed | Houston Astros | Kansas City Royals | $ |
| Jun 24, 2004 | Trade | John Buck | Houston Astros | Kansas City Royals | Trade |
| Jun 24, 2004 | Trade | Mike Wood | Oakland Athletics | Kansas City Royals | Trade |
| Jun 24, 2004 | Trade | Mark Teahen | Oakland Athletics | Kansas City Royals | Trade |
| Jun 24, 2004 | Trade | Carlos Beltran | Kansas City Royals | Houston Astros | Trade |
| Jun 24, 2004 | Trade | Octavio Dotel | Houston Astros | Oakland Athletics | Trade |
| Jun 23, 2004 | Signed as free agent | Todd Williams | — | Baltimore Orioles | Free agent signing |
| Jun 22, 2004 | Signed as free agent | Mike Fetters | — | Arizona Diamondbacks | Free agent signing |
| Jun 22, 2004 | Released | Derrick Gibson | Anaheim Angels | — | Release |
| Jun 22, 2004 | Signed as free agent | Curt Leskanic | — | Boston Red Sox | Free agent signing |
| Jun 21, 2004 | Signed as free agent | Lou Pote | — | San Diego Padres | Free agent signing |
| Jun 21, 2004 | Trade | Denny Bautista | Baltimore Orioles | Kansas City Royals | Trade |
| Jun 21, 2004 | Trade | Jason Grimsley | Kansas City Royals | Baltimore Orioles | Trade |
| Jun 20, 2004 | Released | Jimmy Haynes | Detroit Tigers | — | Release |
| Jun 19, 2004 | Released | Ruben Quevedo | Baltimore Orioles | — | Release |
| Jun 19, 2004 | Released | Wilkin Ruan | Los Angeles Dodgers | — | Release |
| Jun 18, 2004 | Signed | Alfredo Figaro | — | Los Angeles Dodgers | Amateur free agent signing |
| Jun 18, 2004 | Signed | Pedro Florimon | — | Baltimore Orioles | Amateur free agent signing |
| Jun 18, 2004 | Released | Curt Leskanic | Kansas City Royals | — | Release |
| Jun 18, 2004 | Released | David Newhan | Texas Rangers | — | Release |
| Jun 18, 2004 | Signed as free agent | David Newhan | — | Baltimore Orioles | Free agent signing |
| Jun 18, 2004 | Signed as free agent | Keith Osik | — | Florida Marlins | Free agent signing |
| Jun 18, 2004 | Signed as free agent | Donnie Sadler | — | Chicago White Sox | Free agent signing |
| Jun 18, 2004 | Released | Oscar Salazar | Cleveland Indians | — | Release |
| Jun 18, 2004 | Trade | Unnamed | Cincinnati Reds | New York Yankees | $ |
| Jun 18, 2004 | Trade | Charlie Manning | Cincinnati Reds | New York Yankees | Trade |
| Jun 18, 2004 | Trade | Gabe White | New York Yankees | Cincinnati Reds | Trade |
| Jun 17, 2004 | Trade | Scott Youngbauer | Philadelphia Phillies | Cleveland Indians | Trade |
| Jun 17, 2004 | Trade | Unnamed | Florida Marlins | Chicago White Sox | $ |
| Jun 17, 2004 | Trade | Wilson Valdez | Florida Marlins | Chicago White Sox | Trade |
| Jun 17, 2004 | Trade | Billy Koch | Chicago White Sox | Florida Marlins | Trade |
| Jun 17, 2004 | Trade | Jeremy Griffiths | New York Mets | Houston Astros | Trade |
| Jun 17, 2004 | Trade | David Weathers | New York Mets | Houston Astros | Trade |
| Jun 17, 2004 | Trade | Richard Hidalgo | Houston Astros | New York Mets | Trade |
| Jun 16, 2004 | Signed as free agent | Cory Doyne | — | St. Louis Cardinals | Free agent signing |
| Jun 16, 2004 | Signed | Brian Horwitz | — | San Francisco Giants | Amateur free agent signing |
| Jun 16, 2004 | Signed as free agent | Jim Mann | — | Pittsburgh Pirates | Free agent signing |
| Jun 16, 2004 | Trade | Julius Matos | Montreal Expos | Toronto Blue Jays | Trade |
| Jun 16, 2004 | Trade | G.J. Raymundo | Toronto Blue Jays | Montreal Expos | Trade |
| Jun 15, 2004 | Released | David Cortes | Detroit Tigers | — | Release |
| Jun 15, 2004 | Signed as free agent | Luis Lopez | — | Atlanta Braves | Free agent signing |
| Jun 15, 2004 | Released | Jim Mann | New York Yankees | — | Release |
| Jun 15, 2004 | Released | Brad Voyles | Kansas City Royals | — | Release |
| Jun 14, 2004 | Signed as free agent | Winston Abreu | — | Arizona Diamondbacks | Free agent signing |
| Jun 14, 2004 | Signed as free agent | Ricky Gutierrez | — | Chicago Cubs | Free agent signing |
| Jun 14, 2004 | Signed as free agent | Edwards Guzman | — | Baltimore Orioles | Free agent signing |
| Jun 14, 2004 | Released | Willie Morales | Colorado Rockies | — | Release |
| Jun 14, 2004 | Released | Scott Sheldon | Milwaukee Brewers | — | Release |
| Jun 14, 2004 | Released | Todd Williams | Texas Rangers | — | Release |
| Jun 11, 2004 | Signed | Everth Cabrera | — | Colorado Rockies | Amateur free agent signing |
| Jun 11, 2004 | Signed | Matt Daley | — | Colorado Rockies | Amateur free agent signing |
| Jun 11, 2004 | Signed as free agent | Micah Franklin | — | Arizona Diamondbacks | Free agent signing |
| Jun 11, 2004 | Signed as free agent | Rick Helling | — | Texas Rangers | Free agent signing |
| Jun 11, 2004 | Released | Thomas Jacquez | Baltimore Orioles | — | Release |
| Jun 11, 2004 | Released | Luis Lopez | Montreal Expos | — | Release |
| Jun 11, 2004 | Signed as free agent | Quinton McCracken | — | Arizona Diamondbacks | Free agent signing |
| Jun 10, 2004 | Released | Winston Abreu | Los Angeles Dodgers | — | Release |
| Jun 9, 2004 | Released | Quinton McCracken | Seattle Mariners | — | Release |
| Jun 8, 2004 | Released | Pedro Borbon | Montreal Expos | — | Release |
| Jun 8, 2004 | Released | Jeffrey Hammonds | San Francisco Giants | — | Release |
| Jun 8, 2004 | Released | Hansel Izquierdo | New York Yankees | — | Release |
| Jun 8, 2004 | Signed as free agent | Justin Kaye | — | New York Yankees | Free agent signing |
| Jun 7, 2004 | Signed as free agent | Paul Abbott | — | Philadelphia Phillies | Free agent signing |
| Jun 7, 2004 | Signed as free agent | Gary Glover | — | Minnesota Twins | Free agent signing |
| Jun 7, 2004 | Released | Dicky Gonzalez | Tampa Bay Devil Rays | — | Release |
| Jun 7, 2004 | Released | Joey Hamilton | San Diego Padres | — | Release |
| Jun 7, 2004 | Trade | Peter Bergeron | Montreal Expos | Milwaukee Brewers | Trade |
| Jun 7, 2004 | Trade | Saul Rivera | Montreal Expos | Milwaukee Brewers | Trade |
| Jun 7, 2004 | Trade | Jason Childers | Milwaukee Brewers | Montreal Expos | Trade |
| Jun 7, 2004 | Trade | Jason Belcher | Milwaukee Brewers | Montreal Expos | Trade |
| Jun 6, 2004 | Signed as free agent | James Baldwin | — | Detroit Tigers | Free agent signing |
| Jun 6, 2004 | Signed as free agent | Donovan Osborne | — | San Diego Padres | Free agent signing |
| Jun 6, 2004 | Signed as free agent | Alberto Reyes | — | St. Louis Cardinals | Free agent signing |
| Jun 5, 2004 | Released | Gary Glover | Chicago Cubs | — | Release |
| Jun 4, 2004 | Signed as free agent | Scott Forster | — | Florida Marlins | Free agent signing |
| Jun 4, 2004 | Signed as free agent | Kris Keller | — | Texas Rangers | Free agent signing |
| Jun 4, 2004 | Signed as free agent | Peter Munro | — | Houston Astros | Free agent signing |
| Jun 3, 2004 | Released | Paul Abbott | Tampa Bay Devil Rays | — | Release |
| Jun 3, 2004 | Signed as free agent | Pat Mahomes | — | Florida Marlins | Free agent signing |
| Jun 3, 2004 | Released | Keith Osik | Baltimore Orioles | — | Release |
| Jun 3, 2004 | Trade | Robert Ellis | Cleveland Indians | Philadelphia Phillies | Trade |
| Jun 2, 2004 | Signed as free agent | Giovanni Carrara | — | Los Angeles Dodgers | Free agent signing |
| Jun 2, 2004 | Signed as free agent | Ryan Glynn | — | Toronto Blue Jays | Free agent signing |
| Jun 2, 2004 | Released | Rick Helling | Minnesota Twins | — | Release |
| Jun 1, 2004 | Signed as free agent | Cory Aldridge | — | Kansas City Royals | Free agent signing |
| Jun 1, 2004 | Released | Giovanni Carrara | Chicago Cubs | — | Release |
| Jun 1, 2004 | Signed as free agent | Luther Hackman | — | Pittsburgh Pirates | Free agent signing |
| Jun 1, 2004 | Signed as free agent | Gene Kingsale | — | Baltimore Orioles | Free agent signing |
| Jun 1, 2004 | Signed | Kevin Mahar | — | Texas Rangers | Amateur free agent signing |
| Jun 1, 2004 | Released | Pat Mahomes | Montreal Expos | — | Release |
| Jun 1, 2004 | Signed as free agent | Curtis Pride | — | Anaheim Angels | Free agent signing |
| Jun 1, 2004 | Signed as free agent | Mark Quinn | — | St. Louis Cardinals | Free agent signing |
| Jun 1, 2004 | Released | Alberto Reyes | Tampa Bay Devil Rays | — | Release |
| May 31, 2004 | Released | Peter Munro | Minnesota Twins | — | Release |
| May 31, 2004 | Trade | Damian Jackson | Chicago Cubs | Kansas City Royals | Trade |
| May 31, 2004 | Trade | Travis Dawkins | Kansas City Royals | Chicago Cubs | Trade |
| May 30, 2004 | Signed as free agent | Raul Mondesi | — | Anaheim Angels | Free agent signing |
| May 29, 2004 | Released | Ryan Glynn | Atlanta Braves | — | Release |
| May 29, 2004 | Released | Edwards Guzman | Tampa Bay Devil Rays | — | Release |
| May 29, 2004 | Released | Brian Hunter | St. Louis Cardinals | — | Release |
| May 28, 2004 | Released | Juan Acevedo | Pittsburgh Pirates | — | Release |
| May 28, 2004 | Signed as free agent | Carlos Reyes | — | New York Yankees | Free agent signing |
| May 27, 2004 | Signed as free agent | Marvin Benard | — | Toronto Blue Jays | Free agent signing |
| May 27, 2004 | Released | Kris Keller | Chicago White Sox | — | Release |
| May 27, 2004 | Released | Donovan Osborne | New York Yankees | — | Release |
| May 26, 2004 | Signed as free agent | Todd Dunwoody | — | Minnesota Twins | Free agent signing |
| May 25, 2004 | Signed as free agent | Scott Elarton | — | Cleveland Indians | Free agent signing |
| May 25, 2004 | Signed | Sergio Escalona | — | Philadelphia Phillies | Amateur free agent signing |
| May 25, 2004 | Released | Ricky Gutierrez | New York Mets | — | Release |
| May 24, 2004 | Released | Cory Aldridge | Atlanta Braves | — | Release |
| May 24, 2004 | Released | Scott Elarton | Colorado Rockies | — | Release |
| May 24, 2004 | Released | Dave Elder | Atlanta Braves | — | Release |
| May 23, 2004 | Released | Luther Hackman | Cleveland Indians | — | Release |
| May 21, 2004 | Signed as free agent | Bobby Estalella | — | Toronto Blue Jays | Free agent signing |
| May 21, 2004 | Released | Raul Mondesi | Pittsburgh Pirates | — | Release |
| May 21, 2004 | Released | Zach Sorensen | Cleveland Indians | — | Release |
| May 21, 2004 | Signed as free agent | Zach Sorensen | — | Anaheim Angels | Free agent signing |
| May 21, 2004 | Signed as free agent | Craig Wilson | — | New York Yankees | Free agent signing |
| May 20, 2004 | Released | Todd Dunwoody | Cleveland Indians | — | Release |
| May 20, 2004 | Signed as free agent | Raul Gonzalez | — | Cleveland Indians | Free agent signing |
| May 19, 2004 | Released | Ariel Prieto | Chicago Cubs | — | Release |
| May 19, 2004 | Signed as free agent | Scott Wiggins | — | New York Yankees | Free agent signing |
| May 19, 2004 | Trade | Andrew Brown | Los Angeles Dodgers | Cleveland Indians | Trade |
| May 18, 2004 | Signed as free agent | Jimmy Haynes | — | Detroit Tigers | Free agent signing |
| May 18, 2004 | Signed as free agent | Rey Ordonez | — | Chicago Cubs | Free agent signing |
| May 18, 2004 | Signed as free agent | Ariel Prieto | — | Chicago Cubs | Free agent signing |
| May 17, 2004 | Released | Raul Gonzalez | New York Mets | — | Release |
| May 15, 2004 | Trade | Tanyon Sturtze | Los Angeles Dodgers | New York Yankees | Trade |
| May 15, 2004 | Trade | Brian Myrow | New York Yankees | Los Angeles Dodgers | Trade |
| May 14, 2004 | Signed as free agent | Steve Kent | — | Colorado Rockies | Free agent signing |
| May 14, 2004 | Released | Steve Smyth | Atlanta Braves | — | Release |
| May 13, 2004 | Released | Micah Franklin | Chicago White Sox | — | Release |
| May 12, 2004 | Signed as free agent | Pedro Borbon | — | Montreal Expos | Free agent signing |
| May 12, 2004 | Signed as free agent | Brent Butler | — | Atlanta Braves | Free agent signing |
| May 12, 2004 | Signed as free agent | Chris Gissell | — | Colorado Rockies | Free agent signing |
| May 12, 2004 | Released | Jose Nunez | Seattle Mariners | — | Release |
| May 12, 2004 | Released | Rey Ordonez | San Diego Padres | — | Release |
| May 12, 2004 | Signed as free agent | Tom Wilson | — | New York Mets | Free agent signing |
| May 12, 2004 | Signed | Yohan Pino | — | Minnesota Twins | Amateur free agent signing |
| May 11, 2004 | Signed as free agent | Kevin Jarvis | — | Colorado Rockies | Free agent signing |
| May 11, 2004 | Signed as free agent | Corey Lee | — | Anaheim Angels | Free agent signing |
| May 11, 2004 | Signed as free agent | David Manning | — | Chicago Cubs | Free agent signing |
| May 11, 2004 | Signed as free agent | Shawn Sedlacek | — | Chicago Cubs | Free agent signing |
| May 10, 2004 | Released | Jimmy Haynes | Cincinnati Reds | — | Release |
| May 10, 2004 | Released | Gene Kingsale | San Diego Padres | — | Release |
| May 9, 2004 | Released | Javier Martinez | Baltimore Orioles | — | Release |
| May 8, 2004 | Released | Brent Billingsley | Colorado Rockies | — | Release |
| May 8, 2004 | Released | Ken Cloude | Tampa Bay Devil Rays | — | Release |
| May 8, 2004 | Released | Shawn Sedlacek | New York Mets | — | Release |
| May 7, 2004 | Signed as free agent | Jimmy Osting | — | Tampa Bay Devil Rays | Free agent signing |
| May 7, 2004 | Signed as free agent | Ken Ray | — | Chicago White Sox | Free agent signing |
| May 7, 2004 | Signed as free agent | Romulo Sanchez | — | Pittsburgh Pirates | Free agent signing |
| May 7, 2004 | Trade | Joe Horgan | St. Louis Cardinals | Montreal Expos | Trade |
| May 7, 2004 | Trade | Benji DeQuin | Montreal Expos | St. Louis Cardinals | Trade |
| May 6, 2004 | Signed | Juan Francisco | — | Cincinnati Reds | Amateur free agent signing |
| May 6, 2004 | Released | Kevin Jarvis | Seattle Mariners | — | Release |
| May 6, 2004 | Signed as free agent | Josias Manzanillo | — | Florida Marlins | Free agent signing |
| May 5, 2004 | Released | Bryan Corey | Chicago Cubs | — | Release |
| May 5, 2004 | Signed as free agent | Rob Stanifer | — | Montreal Expos | Free agent signing |
| May 3, 2004 | Signed | Denis Phipps | — | Cincinnati Reds | Amateur free agent signing |
| May 2, 2004 | Released | Emil Brown | St. Louis Cardinals | — | Release |
| May 2, 2004 | Released | Tim Young | Cleveland Indians | — | Release |
| May 2004 | Trade | Fernando Rijo | Montreal Expos | Milwaukee Brewers | Trade (date approximate, per the source) |
| Apr 29, 2004 | Signed as free agent | Juan Alvarez | — | Florida Marlins | Free agent signing |
| Apr 29, 2004 | Released | Ariel Prieto | Detroit Tigers | — | Release |
| Apr 29, 2004 | Signed as free agent | Randy Ruiz | — | Philadelphia Phillies | Free agent signing |
| Apr 29, 2004 | Signed as free agent | Jorge Toca | — | Montreal Expos | Free agent signing |
| Apr 29, 2004 | Trade | Jon Connolly | Detroit Tigers | Chicago Cubs | Trade |
| Apr 29, 2004 | Trade | Felix Sanchez | Chicago Cubs | Detroit Tigers | Trade |
| Apr 29, 2004 | Released | Jose De La Torre | Milwaukee Brewers | — | Release |
| Apr 28, 2004 | Signed as free agent | Raul Casanova | — | Boston Red Sox | Free agent signing |
| Apr 28, 2004 | Released | Steve Torrealba | New York Yankees | — | Release |
| Apr 27, 2004 | Signed as free agent | Craig House | — | Baltimore Orioles | Free agent signing |
| Apr 26, 2004 | Signed as free agent | Andres Torres | — | Chicago White Sox | Free agent signing |
| Apr 26, 2004 | Signed as free agent | Jason Tyner | — | Atlanta Braves | Free agent signing |
| Apr 26, 2004 | Signed as free agent | Gerald Williams | — | New York Mets | Free agent signing |
| Apr 25, 2004 | Trade | Rick White | Los Angeles Dodgers | Cleveland Indians | Trade |
| Apr 25, 2004 | Trade | Trey Dyson | Cleveland Indians | Los Angeles Dodgers | Trade |
| Apr 25, 2004 | Trade | Russell Branyan | Atlanta Braves | Cleveland Indians | Trade |
| Apr 25, 2004 | Trade | Scott Sturkie | Cleveland Indians | Atlanta Braves | Trade |
| Apr 23, 2004 | Signed | Henry Sosa | — | San Francisco Giants | Amateur free agent signing |
| Apr 23, 2004 | Released | Tom Wilson | Oakland Athletics | — | Release |
| Apr 23, 2004 | Trade | Joaquin Arias | New York Yankees | Texas Rangers | Trade |
| Apr 17, 2004 | Trade | Chad Harville | Oakland Athletics | Houston Astros | Trade |
| Apr 17, 2004 | Trade | Kirk Saarloos | Houston Astros | Oakland Athletics | Trade |
| Apr 16, 2004 | Signed as free agent | Ricky Bottalico | — | New York Mets | Free agent signing |
| Apr 16, 2004 | Released | Corey Lee | New York Yankees | — | Release |
| Apr 16, 2004 | Signed as free agent | Mike Moriarty | — | Pittsburgh Pirates | Free agent signing |
| Apr 15, 2004 | Signed as free agent | Jason Jimenez | — | Philadelphia Phillies | Free agent signing |
| Apr 15, 2004 | Signed as free agent | Eric Owens | — | Detroit Tigers | Free agent signing |
| Apr 14, 2004 | Signed as free agent | Joe Vitiello | — | Detroit Tigers | Free agent signing |
| Apr 13, 2004 | Signed as free agent | Mike Difelice | — | Detroit Tigers | Free agent signing |
| Apr 13, 2004 | Signed as free agent | Brian Esposito | — | Texas Rangers | Free agent signing |
| Apr 13, 2004 | Signed as free agent | Allen Levrault | — | Seattle Mariners | Free agent signing |
| Apr 13, 2004 | Trade | Aaron Looper | Los Angeles Dodgers | Seattle Mariners | Trade |
| Apr 13, 2004 | Trade | Glenn Bott | Seattle Mariners | Los Angeles Dodgers | Trade |
| Apr 12, 2004 | Signed as free agent | Trent Hubbard | — | Chicago Cubs | Free agent signing |
| Apr 12, 2004 | Signed as free agent | Scott Sauerbeck | — | Cleveland Indians | Free agent signing |
| Apr 12, 2004 | Signed as free agent | Esteban Yan | — | Detroit Tigers | Free agent signing |
| Apr 11, 2004 | Signed as free agent | Joe Beimel | — | Minnesota Twins | Free agent signing |
| Apr 10, 2004 | Signed as free agent | Bubba Trammell | — | Tampa Bay Devil Rays | Free agent signing |
| Apr 9, 2004 | Signed as free agent | Mark DiFelice | — | Baltimore Orioles | Free agent signing |
| Apr 9, 2004 | Signed as free agent | Gregg Zaun | — | Toronto Blue Jays | Free agent signing |
| Apr 8, 2004 | Signed as free agent | Gary Matthews | — | Texas Rangers | Free agent signing |
| Apr 8, 2004 | Signed as free agent | Tanyon Sturtze | — | Los Angeles Dodgers | Free agent signing |
| Apr 8, 2004 | Released | Joe Vitiello | Montreal Expos | — | Release |
| Apr 8, 2004 | Trade | Unnamed | Kansas City Royals | Colorado Rockies | $ |
| Apr 8, 2004 | Trade | Chris Fallon | Kansas City Royals | Colorado Rockies | Trade |
| Apr 8, 2004 | Trade | Zach McClellan | Kansas City Royals | Colorado Rockies | Trade |
| Apr 8, 2004 | Trade | Justin Huisman | Colorado Rockies | Kansas City Royals | Trade |
| Apr 8, 2004 | Trade | Marty McLeary | Florida Marlins | San Diego Padres | Trade |
| Apr 8, 2004 | Trade | Bryan Gaal | San Diego Padres | Florida Marlins | Trade |
| Apr 7, 2004 | Signed as free agent | Jeff Austin | — | Cincinnati Reds | Free agent signing |
| Apr 7, 2004 | Released | Ricky Bottalico | New York Mets | — | Release |
| Apr 7, 2004 | Released | Chris Gissell | San Francisco Giants | — | Release |
| Apr 7, 2004 | Released | Jason Tyner | Texas Rangers | — | Release |
| Apr 7, 2004 | Released | Chris Widger | St. Louis Cardinals | — | Release |
| Apr 6, 2004 | Signed as free agent | Kenny Kelly | — | Cincinnati Reds | Free agent signing |
| Apr 6, 2004 | Signed as free agent | Anthony Sanders | — | Colorado Rockies | Free agent signing |
| Apr 5, 2004 | Signed as free agent | Javier Cardona | — | New York Mets | Free agent signing |
| Apr 5, 2004 | Signed as free agent | Giovanni Carrara | — | Chicago Cubs | Free agent signing |
| Apr 5, 2004 | Signed as free agent | Benji Gil | — | Chicago Cubs | Free agent signing |
| Apr 5, 2004 | Signed as free agent | Andrew Lorraine | — | Pittsburgh Pirates | Free agent signing |
| Apr 5, 2004 | Signed as free agent | Mark McLemore | — | Oakland Athletics | Free agent signing |
| Apr 5, 2004 | Signed as free agent | Kevin Orie | — | Cleveland Indians | Free agent signing |
| Apr 5, 2004 | Signed as free agent | Glendon Rusch | — | Chicago Cubs | Free agent signing |
| Apr 5, 2004 | Released | Anthony Sanders | Colorado Rockies | — | Release |
| Apr 5, 2004 | Signed as free agent | Terry Shumpert | — | Pittsburgh Pirates | Free agent signing |
| Apr 4, 2004 | Released | Jeff Austin | Cincinnati Reds | — | Release |
| Apr 4, 2004 | Trade | Wilson Delgado | St. Louis Cardinals | New York Mets | Trade |
| Apr 4, 2004 | Trade | Roger Cedeno | New York Mets | St. Louis Cardinals | Trade |
| Apr 3, 2004 | Released | Juan Alvarez | New York Yankees | — | Release |
| Apr 3, 2004 | Released | Mike Difelice | Detroit Tigers | — | Release |
| Apr 3, 2004 | Released | Trent Hubbard | Chicago Cubs | — | Release |
| Apr 3, 2004 | Released | Kenny Kelly | New York Mets | — | Release |
| Apr 3, 2004 | Released | Pascual Matos | Colorado Rockies | — | Release |
| Apr 3, 2004 | Released | Mark McLemore | Baltimore Orioles | — | Release |
| Apr 3, 2004 | Released | Mike Moriarty | Colorado Rockies | — | Release |
| Apr 3, 2004 | Released | Craig Wilson | Chicago Cubs | — | Release |
| Apr 3, 2004 | Signed as free agent | Tom Wilson | — | Oakland Athletics | Free agent signing |
| Apr 3, 2004 | Trade | Antonio Perez | Tampa Bay Devil Rays | Los Angeles Dodgers | Trade |
| Apr 3, 2004 | Trade | Jason Romano | Los Angeles Dodgers | Tampa Bay Devil Rays | Trade |
| Apr 3, 2004 | Trade | Ben Howard | San Diego Padres | Florida Marlins | Trade |
| Apr 3, 2004 | Trade | Blaine Neal | Florida Marlins | San Diego Padres | Trade |
| Apr 3, 2004 | Trade | Aaron Looper | Seattle Mariners | Los Angeles Dodgers | Trade |
| Apr 3, 2004 | Trade | Ryan Ketchner | Seattle Mariners | Los Angeles Dodgers | Trade |
| Apr 3, 2004 | Trade | Jolbert Cabrera | Los Angeles Dodgers | Seattle Mariners | Trade |
| Apr 3, 2004 | Trade | Milton Bradley | Cleveland Indians | Los Angeles Dodgers | Trade |
| Apr 3, 2004 | Trade | Franklin Gutierrez | Los Angeles Dodgers | Cleveland Indians | Trade |
| Apr 3, 2004 | Trade | Chris Young | Montreal Expos | Texas Rangers | Trade |
| Apr 3, 2004 | Trade | Josh McKinley | Montreal Expos | Texas Rangers | Trade |
| Apr 3, 2004 | Trade | Einar Diaz | Texas Rangers | Montreal Expos | Trade |
| Apr 3, 2004 | Trade | Justin Echols | Texas Rangers | Montreal Expos | Trade |
| Apr 2, 2004 | Released | Brian Banks | Florida Marlins | — | Release |
| Apr 2, 2004 | Released | Matt DeWitt | Cleveland Indians | — | Release |
| Apr 2, 2004 | Signed as free agent | Damian Jackson | — | Chicago Cubs | Free agent signing |
| Apr 2, 2004 | Signed as free agent | Jason Jacome | — | San Francisco Giants | Free agent signing |
| Apr 2, 2004 | Released | Steve Kent | Florida Marlins | — | Release |
| Apr 2, 2004 | Signed as free agent | Ruddy Lugo | — | Florida Marlins | Free agent signing |
| Apr 2, 2004 | Released | David Manning | Florida Marlins | — | Release |
| Apr 2, 2004 | Released | Gary Matthews | Atlanta Braves | — | Release |
| Apr 2, 2004 | Released | Carlos Reyes | Tampa Bay Devil Rays | — | Release |
| Apr 2, 2004 | Released | Roy Smith | Cleveland Indians | — | Release |
| Apr 2, 2004 | Released | Rob Stanifer | Tampa Bay Devil Rays | — | Release |
| Apr 2, 2004 | Released | Tanyon Sturtze | Florida Marlins | — | Release |
| Apr 2, 2004 | Released | Bubba Trammell | Los Angeles Dodgers | — | Release |
| Apr 2, 2004 | Released | Gerald Williams | Florida Marlins | — | Release |
| Apr 2, 2004 | Signed as free agent | Jamey Wright | — | Kansas City Royals | Free agent signing |
| Apr 1, 2004 | Signed as free agent | Erick Almonte | — | Colorado Rockies | Free agent signing |
| Apr 1, 2004 | Released | Craig House | Baltimore Orioles | — | Release |
| Apr 1, 2004 | Released | Andrew Lorraine | Minnesota Twins | — | Release |
| Apr 1, 2004 | Released | Scott McClain | Chicago Cubs | — | Release |
| Apr 1, 2004 | Signed as free agent | Elvis Peña | — | Colorado Rockies | Free agent signing |
| Apr 1, 2004 | Released | Mark Quinn | St. Louis Cardinals | — | Release |
| Apr 1, 2004 | Released | Glendon Rusch | Texas Rangers | — | Release |
| Apr 1, 2004 | Released | Scott Wiggins | Milwaukee Brewers | — | Release |
| Apr 1, 2004 | Trade | Steve Colyer | Los Angeles Dodgers | Detroit Tigers | Trade |
| Apr 1, 2004 | Trade | Cody Ross | Detroit Tigers | Los Angeles Dodgers | Trade |
| Apr 1, 2004 | Trade | Brian Sanches | San Diego Padres | Philadelphia Phillies | Trade |
| Apr 2004 | Released | John Foster | Milwaukee Brewers | — | Release |
| Mar 31, 2004 | Released | Joe Beimel | Pittsburgh Pirates | — | Release |
| Mar 31, 2004 | Signed as free agent | Deivi Cruz | — | San Francisco Giants | Free agent signing |
| Mar 31, 2004 | Released | Mark DiFelice | Colorado Rockies | — | Release |
| Mar 31, 2004 | Released | Cory Doyne | San Diego Padres | — | Release |
| Mar 31, 2004 | Released | Brian Esposito | Anaheim Angels | — | Release |
| Mar 31, 2004 | Released | Jeff Farnsworth | Montreal Expos | — | Release |
| Mar 31, 2004 | Released | Justin Kaye | San Diego Padres | — | Release |
| Mar 31, 2004 | Released | Scott Patterson | Seattle Mariners | — | Release |
| Mar 31, 2004 | Released | Edwar Ramirez | Anaheim Angels | — | Release |
| Mar 31, 2004 | Released | Terry Shumpert | Boston Red Sox | — | Release |
| Mar 31, 2004 | Released | Jorge Toca | Pittsburgh Pirates | — | Release |
| Mar 31, 2004 | Signed | Raul Valdes | — | Chicago Cubs | Amateur free agent signing |
| Mar 31, 2004 | Released | Tom Wilson | San Diego Padres | — | Release |
| Mar 31, 2004 | Released | Esteban Yan | Detroit Tigers | — | Release |
| Mar 31, 2004 | Trade | Jeriome Robertson | Houston Astros | Cleveland Indians | Trade |
| Mar 31, 2004 | Trade | Luke Scott | Cleveland Indians | Houston Astros | Trade |
| Mar 30, 2004 | Signed as free agent | Andy Ashby | — | San Diego Padres | Free agent signing |
| Mar 30, 2004 | Signed as free agent | Nate Bland | — | Chicago Cubs | Free agent signing |
| Mar 30, 2004 | Signed as free agent | Felix Escalona | — | New York Yankees | Free agent signing |
| Mar 30, 2004 | Released | Benji Gil | Colorado Rockies | — | Release |
| Mar 30, 2004 | Signed as free agent | Junior Herndon | — | Kansas City Royals | Free agent signing |
| Mar 30, 2004 | Signed as free agent | Delvin James | — | Anaheim Angels | Free agent signing |
| Mar 30, 2004 | Released | Robin Jennings | Tampa Bay Devil Rays | — | Release |
| Mar 30, 2004 | Signed as free agent | Todd Jones | — | Cincinnati Reds | Free agent signing |
| Mar 30, 2004 | Signed as free agent | Joe Nelson | — | Boston Red Sox | Free agent signing |
| Mar 30, 2004 | Released | Eric Owens | Seattle Mariners | — | Release |
| Mar 30, 2004 | Released | Tanyon Sturtze | Los Angeles Dodgers | — | Release |
| Mar 30, 2004 | Signed as free agent | Tanyon Sturtze | — | Florida Marlins | Free agent signing |
| Mar 30, 2004 | Signed as free agent | Dave Veres | — | San Francisco Giants | Free agent signing |
| Mar 30, 2004 | Trade | Carlos Villanueva | San Francisco Giants | Milwaukee Brewers | Trade |
| Mar 30, 2004 | Trade | Glenn Woolard | San Francisco Giants | Milwaukee Brewers | Trade |
| Mar 30, 2004 | Trade | Leo Estrella | Milwaukee Brewers | San Francisco Giants | Trade |
| Mar 30, 2004 | Trade | Wayne Franklin | Milwaukee Brewers | San Francisco Giants | Trade |
| Mar 29, 2004 | Released | Nate Bland | Houston Astros | — | Release |
| Mar 29, 2004 | Released | Devern Hansack | Houston Astros | — | Release |
| Mar 29, 2004 | Signed as free agent | Ugueth Urbina | — | Detroit Tigers | Free agent signing |
| Mar 29, 2004 | Trade | Kerry Robinson | St. Louis Cardinals | San Diego Padres | Trade |
| Mar 29, 2004 | Trade | Brian Hunter | San Diego Padres | St. Louis Cardinals | Trade |
| Mar 29, 2004 | Trade | Jason Frasor | Los Angeles Dodgers | Toronto Blue Jays | Trade |
| Mar 29, 2004 | Trade | Jayson Werth | Toronto Blue Jays | Los Angeles Dodgers | Trade |
| Mar 29, 2004 | Trade | Alejandro Machado | Milwaukee Brewers | Montreal Expos | Trade |
| Mar 28, 2004 | Released | Allen Levrault | St. Louis Cardinals | — | Release |
| Mar 28, 2004 | Released | Ruddy Lugo | Houston Astros | — | Release |
| Mar 28, 2004 | Released | Elvis Peña | Houston Astros | — | Release |
| Mar 28, 2004 | Released | Luis Pineda | Los Angeles Dodgers | — | Release |
| Mar 28, 2004 | Released | Brad Ziegler | Philadelphia Phillies | — | Release |
| Mar 27, 2004 | Released | Benito Baez | Cincinnati Reds | — | Release |
| Mar 27, 2004 | Released | Giovanni Carrara | Cleveland Indians | — | Release |
| Mar 27, 2004 | Released | Damian Jackson | Colorado Rockies | — | Release |
| Mar 27, 2004 | Released | Jamey Wright | Chicago Cubs | — | Release |
| Mar 27, 2004 | Trade | Randy Choate | Montreal Expos | Arizona Diamondbacks | Trade |
| Mar 27, 2004 | Trade | John Patterson | Arizona Diamondbacks | Montreal Expos | Trade |
| Mar 27, 2004 | Trade | Matt Ginter | Chicago White Sox | New York Mets | Trade |
| Mar 27, 2004 | Trade | Timo Perez | New York Mets | Chicago White Sox | Trade |
| Mar 26, 2004 | Released | Erick Almonte | New York Yankees | — | Release |
| Mar 26, 2004 | Released | Gabe Molina | Chicago Cubs | — | Release |
| Mar 26, 2004 | Released | Armando Rios | Florida Marlins | — | Release |
| Mar 26, 2004 | Released | Randy Ruiz | St. Louis Cardinals | — | Release |
| Mar 26, 2004 | Released | Dave Veres | Houston Astros | — | Release |
| Mar 26, 2004 | Trade | Jung Bong | Atlanta Braves | Cincinnati Reds | Trade |
| Mar 26, 2004 | Trade | Bubba Nelson | Atlanta Braves | Cincinnati Reds | Trade |
| Mar 26, 2004 | Trade | Chris Reitsma | Cincinnati Reds | Atlanta Braves | Trade |
| Mar 25, 2004 | Trade | Andy Pratt | Atlanta Braves | Chicago Cubs | Trade |
| Mar 25, 2004 | Trade | Richard Lewis | Atlanta Braves | Chicago Cubs | Trade |
| Mar 25, 2004 | Trade | Juan Cruz | Chicago Cubs | Atlanta Braves | Trade |
| Mar 25, 2004 | Trade | Steve Smyth | Chicago Cubs | Atlanta Braves | Trade |
| Mar 25, 2004 | Trade | Mike Lamb | New York Yankees | Houston Astros | Trade |
| Mar 25, 2004 | Trade | Juan De Leon | Houston Astros | New York Yankees | Trade |
| Mar 24, 2004 | Released | Pedro Borbon | San Diego Padres | — | Release |
| Mar 24, 2004 | Released | Deivi Cruz | Tampa Bay Devil Rays | — | Release |
| Mar 24, 2004 | Released | Todd Jones | Tampa Bay Devil Rays | — | Release |
| Mar 24, 2004 | Released | Fernando Tatis | Tampa Bay Devil Rays | — | Release |
| Mar 23, 2004 | Signed as free agent | Greg Maddux | — | Chicago Cubs | Free agent signing |
| Mar 23, 2004 | Signed as free agent | Fred McGriff | — | Tampa Bay Devil Rays | Free agent signing |
| Mar 23, 2004 | Signed as free agent | Bry Nelson | — | Chicago White Sox | Free agent signing |
| Mar 22, 2004 | Signed as free agent | Nick Bierbrodt | — | Texas Rangers | Free agent signing |
| Mar 22, 2004 | Signed as free agent | Alberto Castillo | — | Kansas City Royals | Free agent signing |
| Mar 22, 2004 | Released | Delvin James | Florida Marlins | — | Release |
| Mar 21, 2004 | Signed as free agent | Ben Petrick | — | San Diego Padres | Free agent signing |
| Mar 21, 2004 | Trade | Tony Womack | Boston Red Sox | St. Louis Cardinals | Trade |
| Mar 21, 2004 | Trade | Matt Duff | St. Louis Cardinals | Boston Red Sox | Trade |
| Mar 18, 2004 | Released | Brent Butler | St. Louis Cardinals | — | Release |
| Mar 18, 2004 | Released | Raul Casanova | Baltimore Orioles | — | Release |
| Mar 18, 2004 | Released | Mike Crudale | Milwaukee Brewers | — | Release |
| Mar 17, 2004 | Released | Alberto Castillo | San Francisco Giants | — | Release |
| Mar 17, 2004 | Signed as free agent | Joe Dillon | — | Florida Marlins | Free agent signing |
| Mar 17, 2004 | Released | Alan Mills | Tampa Bay Devil Rays | — | Release |
| Mar 17, 2004 | Signed as free agent | Derek Thompson | — | Los Angeles Dodgers | Free agent signing |
| Mar 17, 2004 | Signed as free agent | John Vander Wal | — | Cincinnati Reds | Free agent signing |
| Mar 16, 2004 | Signed | Johnny Cueto | — | Cincinnati Reds | Amateur free agent signing |
| Mar 16, 2004 | Signed as free agent | Kit Pellow | — | Colorado Rockies | Free agent signing |
| Mar 16, 2004 | Released | Ben Petrick | Detroit Tigers | — | Release |
| Mar 15, 2004 | Signed as free agent | Stubby Clapp | — | Cleveland Indians | Free agent signing |
| Mar 15, 2004 | Signed as free agent | Mike Oquist | — | Oakland Athletics | Free agent signing |
| Mar 15, 2004 | Signed as free agent | Roy Smith | — | Cleveland Indians | Free agent signing |
| Mar 15, 2004 | Signed as free agent | B. J. Surhoff | — | Baltimore Orioles | Free agent signing |
| Mar 14, 2004 | Released | John Vander Wal | Cincinnati Reds | — | Release |
| Mar 12, 2004 | Signed as free agent | Orlando Hernandez | — | New York Yankees | Free agent signing |
| Mar 12, 2004 | Released | Jason Jimenez | Florida Marlins | — | Release |
| Mar 12, 2004 | Released | Romulo Sanchez | Los Angeles Dodgers | — | Release |
| Mar 12, 2004 | Released | Bill Simas | Los Angeles Dodgers | — | Release |
| Mar 11, 2004 | Released | Cedrick Bowers | Florida Marlins | — | Release |
| Mar 11, 2004 | Released | Nelson Cruz | Florida Marlins | — | Release |
| Mar 10, 2004 | Released | Marvin Benard | Chicago White Sox | — | Release |
| Mar 9, 2004 | Signed as free agent | Nate Bland | — | Houston Astros | Free agent signing |
| Mar 9, 2004 | Signed as free agent | Mike Glavine | — | New York Mets | Free agent signing |
| Mar 9, 2004 | Signed as free agent | Mike Thurman | — | New York Yankees | Free agent signing |
| Mar 8, 2004 | Released | Tim Christman | Detroit Tigers | — | Release |
| Mar 8, 2004 | Signed as free agent | Chris Donnels | — | Colorado Rockies | Free agent signing |
| Mar 8, 2004 | Signed as free agent | Shawn Estes | — | Colorado Rockies | Free agent signing |
| Mar 8, 2004 | Signed as free agent | Craig House | — | Baltimore Orioles | Free agent signing |
| Mar 8, 2004 | Signed as free agent | George Lombard | — | Boston Red Sox | Free agent signing |
| Mar 8, 2004 | Signed as free agent | Jose Nieves | — | San Diego Padres | Free agent signing |
| Mar 8, 2004 | Signed as free agent | Scott Patterson | — | Seattle Mariners | Free agent signing with first major-league team |
| Mar 8, 2004 | Signed as free agent | Jose Rodriguez | — | Baltimore Orioles | Free agent signing |
| Mar 8, 2004 | Released | Gregg Zaun | Montreal Expos | — | Release |
| Mar 5, 2004 | Signed as free agent | Scott Elarton | — | Colorado Rockies | Free agent signing |
| Mar 5, 2004 | Released | Pete Walker | Toronto Blue Jays | — | Release |
| Mar 4, 2004 | Signed as free agent | Hansel Izquierdo | — | New York Yankees | Free agent signing |
| Mar 4, 2004 | Released | Robert Person | Chicago White Sox | — | Release |
| Mar 4, 2004 | Signed as free agent | John Rodriguez | — | New York Yankees | Free agent signing |
| Mar 2, 2004 | Signed as free agent | Travis Lee | — | New York Yankees | Free agent signing |
| Mar 1, 2004 | Released | Aaron Boone | New York Yankees | — | Release |
| Mar 1, 2004 | Signed as free agent | Robin Jennings | — | Tampa Bay Devil Rays | Free agent signing |
| Mar 1, 2004 | Signed as free agent | Pat Mahomes | — | Montreal Expos | Free agent signing |
| Mar 1, 2004 | Signed as free agent | Joe Vitiello | — | Montreal Expos | Free agent signing |
| Feb 26, 2004 | Signed as free agent | Brian McNichol | — | Chicago White Sox | Free agent signing |
| Feb 25, 2004 | Signed as free agent | Bobby Estalella | — | Arizona Diamondbacks | Free agent signing |
| Feb 25, 2004 | Signed | Eduardo Nunez | — | New York Yankees | Amateur free agent signing |
| Feb 25, 2004 | Signed as free agent | Dan Reichert | — | Milwaukee Brewers | Free agent signing |
| Feb 25, 2004 | Signed as free agent | Nerio Rodriguez | — | New York Yankees | Free agent signing |
| Feb 25, 2004 | Signed as free agent | Scott Service | — | Arizona Diamondbacks | Free agent signing |
| Feb 25, 2004 | Signed as free agent | Ryan Thompson | — | Houston Astros | Free agent signing |
| Feb 24, 2004 | Signed as free agent | Raul Mondesi | — | Pittsburgh Pirates | Free agent signing |
| Feb 20, 2004 | Signed as free agent | Frank Castillo | — | Boston Red Sox | Free agent signing |
| Feb 19, 2004 | Signed as free agent | Doug Brocail | — | Texas Rangers | Free agent signing |
| Feb 19, 2004 | Signed as free agent | Russ Johnson | — | Chicago Cubs | Free agent signing |
| Feb 19, 2004 | Signed as free agent | Andrew Lorraine | — | Minnesota Twins | Free agent signing |
| Feb 19, 2004 | Signed as free agent | Chris Michalak | — | Milwaukee Brewers | Free agent signing |
| Feb 19, 2004 | Signed as free agent | Santiago Perez | — | Chicago Cubs | Free agent signing |
| Feb 19, 2004 | Signed as free agent | Brian Rose | — | Cincinnati Reds | Free agent signing |
| Feb 19, 2004 | Signed as free agent | Randall Simon | — | Pittsburgh Pirates | Free agent signing |
| Feb 18, 2004 | Signed as free agent | Doug Creek | — | St. Louis Cardinals | Free agent signing |
| Feb 18, 2004 | Signed as free agent | Matt DeWitt | — | Cleveland Indians | Free agent signing |
| Feb 18, 2004 | Signed as free agent | Ray Lankford | — | St. Louis Cardinals | Free agent signing |
| Feb 17, 2004 | Signed as free agent | Dave Elder | — | Atlanta Braves | Free agent signing |
| Feb 17, 2004 | Signed as free agent | Randy Keisler | — | New York Mets | Free agent signing |
| Feb 17, 2004 | Signed as free agent | Brian Moehler | — | Atlanta Braves | Free agent signing |
| Feb 17, 2004 | Signed as free agent | Kevin Nicholson | — | Pittsburgh Pirates | Free agent signing |
| Feb 16, 2004 | Signed as free agent | Doug Glanville | — | Philadelphia Phillies | Free agent signing |
| Feb 16, 2004 | Signed as free agent | Alan Mills | — | Tampa Bay Devil Rays | Free agent signing |
| Feb 16, 2004 | Signed as free agent | Craig Wilson | — | Chicago Cubs | Free agent signing |
| Feb 16, 2004 | Trade | Unnamed | Texas Rangers | New York Yankees | $ |
| Feb 16, 2004 | Trade | Alex Rodriguez | Texas Rangers | New York Yankees | Trade |
| Feb 16, 2004 | Trade | Alfonso Soriano | New York Yankees | Texas Rangers | Trade |
| Feb 14, 2004 | Signed as free agent | Nelson Cruz | — | Florida Marlins | Free agent signing |
| Feb 14, 2004 | Signed as free agent | Carlos Febles | — | Boston Red Sox | Free agent signing |
| Feb 14, 2004 | Signed as free agent | Orlando Merced | — | Pittsburgh Pirates | Free agent signing |
| Feb 13, 2004 | Signed as free agent | Robert Ellis | — | Cleveland Indians | Free agent signing |
| Feb 13, 2004 | Signed | Marcos Mateo | — | Cincinnati Reds | Amateur free agent signing |
| Feb 13, 2004 | Signed as free agent | Matt Miller | — | Cleveland Indians | Free agent signing |
| Feb 13, 2004 | Signed as free agent | Rodney Myers | — | Los Angeles Dodgers | Free agent signing |
| Feb 13, 2004 | Signed | Atahualpa Severino | — | Montreal Expos | Amateur free agent signing |
| Feb 13, 2004 | Signed as free agent | Tony Womack | — | Boston Red Sox | Free agent signing |
| Feb 12, 2004 | Signed as free agent | John Mabry | — | St. Louis Cardinals | Free agent signing |
| Feb 12, 2004 | Signed as free agent | Rudy Seanez | — | Kansas City Royals | Free agent signing |
| Feb 11, 2004 | Signed as free agent | Paxton Crawford | — | Cincinnati Reds | Free agent signing |
| Feb 11, 2004 | Signed as free agent | Will Ohman | — | Chicago Cubs | Free agent signing |
| Feb 10, 2004 | Signed as free agent | Juan Alvarez | — | New York Yankees | Free agent signing |
| Feb 10, 2004 | Signed as free agent | Midre Cummings | — | Tampa Bay Devil Rays | Free agent signing |
| Feb 10, 2004 | Signed as free agent | Denny Hocking | — | Colorado Rockies | Free agent signing |
| Feb 10, 2004 | Signed | Shairon Martis | — | San Francisco Giants | Amateur free agent signing |
| Feb 10, 2004 | Signed as free agent | Terry Mulholland | — | Seattle Mariners | Free agent signing |
| Feb 10, 2004 | Signed as free agent | Ron Villone | — | Seattle Mariners | Free agent signing |
| Feb 9, 2004 | Signed as free agent | James Baldwin | — | New York Mets | Free agent signing |
| Feb 9, 2004 | Signed as free agent | Ricky Bottalico | — | New York Mets | Free agent signing |
| Feb 9, 2004 | Released | Bobby Estalella | Detroit Tigers | — | Release |
| Feb 9, 2004 | Signed as free agent | Charles Gipson | — | Tampa Bay Devil Rays | Free agent signing |
| Feb 9, 2004 | Signed as free agent | David Lundquist | — | Pittsburgh Pirates | Free agent signing |
| Feb 9, 2004 | Signed as free agent | Jason Middlebrook | — | Anaheim Angels | Free agent signing |
| Feb 9, 2004 | Signed as free agent | Dave Nilsson | — | Atlanta Braves | Free agent signing |
| Feb 9, 2004 | Signed as free agent | Luis Ordaz | — | Tampa Bay Devil Rays | Free agent signing |
| Feb 8, 2004 | Signed as free agent | Eric Owens | — | Seattle Mariners | Free agent signing |
| Feb 8, 2004 | Signed as free agent | Todd Zeile | — | New York Mets | Free agent signing |
| Feb 7, 2004 | Signed as free agent | Donovan Osborne | — | New York Yankees | Free agent signing |
| Feb 6, 2004 | Signed as free agent | Ellis Burks | — | Boston Red Sox | Free agent signing |
| Feb 6, 2004 | Signed as free agent | Wil Cordero | — | Florida Marlins | Free agent signing |
| Feb 6, 2004 | Signed as free agent | Derrick Gibson | — | Anaheim Angels | Free agent signing |
| Feb 6, 2004 | Signed as free agent | Eric Karros | — | Oakland Athletics | Free agent signing |
| Feb 6, 2004 | Signed as free agent | Damon Minor | — | San Francisco Giants | Free agent signing |
| Feb 6, 2004 | Signed as free agent | Jose Offerman | — | Minnesota Twins | Free agent signing |
| Feb 6, 2004 | Signed as free agent | Darren Oliver | — | Florida Marlins | Free agent signing |
| Feb 6, 2004 | Signed as free agent | Ivan Rodriguez | — | Detroit Tigers | Free agent signing |
| Feb 5, 2004 | Signed as free agent | Benito Baez | — | Cincinnati Reds | Free agent signing |
| Feb 5, 2004 | Signed as free agent | Clay Bellinger | — | Baltimore Orioles | Free agent signing |
| Feb 5, 2004 | Signed as free agent | Brent Billingsley | — | Colorado Rockies | Free agent signing |
| Feb 5, 2004 | Signed as free agent | Russell Branyan | — | Atlanta Braves | Free agent signing |
| Feb 5, 2004 | Signed as free agent | Mark Guthrie | — | Pittsburgh Pirates | Free agent signing |
| Feb 5, 2004 | Signed as free agent | Antonio Osuna | — | San Diego Padres | Free agent signing |
| Feb 5, 2004 | Signed as free agent | Rob Ryan | — | Houston Astros | Free agent signing |
| Feb 5, 2004 | Signed as free agent | Anthony Sanders | — | Colorado Rockies | Free agent signing |
| Feb 5, 2004 | Signed as free agent | Esix Snead | — | New York Mets | Free agent signing |
| Feb 5, 2004 | Trade | Mike Lamb | Texas Rangers | New York Yankees | Trade |
| Feb 5, 2004 | Trade | Jose Garcia | New York Yankees | Texas Rangers | Trade |
| Feb 4, 2004 | Signed as free agent | Brad Clontz | — | Texas Rangers | Free agent signing |
| Feb 4, 2004 | Signed as free agent | Joe Girardi | — | New York Yankees | Free agent signing |
| Feb 4, 2004 | Signed as free agent | Jose Hernandez | — | Los Angeles Dodgers | Free agent signing |
| Feb 4, 2004 | Signed as free agent | Scott MacRae | — | Cincinnati Reds | Free agent signing |
| Feb 4, 2004 | Signed as free agent | Mark McLemore | — | Baltimore Orioles | Free agent signing |
| Feb 4, 2004 | Signed as free agent | Franklin Nunez | — | Tampa Bay Devil Rays | Free agent signing |
| Feb 3, 2004 | Signed as free agent | Scott Erickson | — | New York Mets | Free agent signing |
| Feb 3, 2004 | Signed as free agent | Mike Kelly | — | New York Yankees | Free agent signing |
| Feb 3, 2004 | Signed as free agent | Vladimir Nunez | — | Colorado Rockies | Free agent signing |
| Feb 3, 2004 | Signed as free agent | Armando Rios | — | Florida Marlins | Free agent signing |
| Feb 3, 2004 | Signed as free agent | Terry Shumpert | — | Boston Red Sox | Free agent signing |
| Feb 2, 2004 | Signed as free agent | Pascual Matos | — | Colorado Rockies | Free agent signing |
| Feb 2, 2004 | Signed as free agent | Jesus Sanchez | — | Cincinnati Reds | Free agent signing |
| Feb 2, 2004 | Signed as free agent | Dave Veres | — | Houston Astros | Free agent signing |
| Feb 1, 2004 | Signed as free agent | Charlie Greene | — | Chicago Cubs | Free agent signing |
| Feb 1, 2004 | Signed as free agent | Elvis Peña | — | Houston Astros | Free agent signing |
| Feb 1, 2004 | Signed as free agent | Steve Torrealba | — | New York Yankees | Free agent signing |
| Jan 30, 2004 | Signed as free agent | Tim Byrdak | — | San Diego Padres | Free agent signing |
| Jan 30, 2004 | Signed as free agent | Jesse Levis | — | New York Mets | Free agent signing |
| Jan 30, 2004 | Signed as free agent | Jose Mesa | — | Pittsburgh Pirates | Free agent signing |
| Jan 30, 2004 | Signed | Jose De La Torre | — | Milwaukee Brewers | Amateur free agent signing |
| Jan 29, 2004 | Signed as free agent | Mike Johnson | — | Montreal Expos | Free agent signing |
| Jan 29, 2004 | Signed as free agent | Shane Spencer | — | New York Mets | Free agent signing |
| Jan 28, 2004 | Signed as free agent | Darren Bragg | — | New York Yankees | Free agent signing |
| Jan 28, 2004 | Signed as free agent | Mike Colangelo | — | Florida Marlins | Free agent signing |
| Jan 28, 2004 | Signed as free agent | Tyler Houston | — | New York Yankees | Free agent signing |
| Jan 28, 2004 | Signed as free agent | Thomas Jacquez | — | Baltimore Orioles | Free agent signing |
| Jan 28, 2004 | Signed as free agent | Justin Kaye | — | San Diego Padres | Free agent signing |
| Jan 28, 2004 | Signed as free agent | Jose Lima | — | Los Angeles Dodgers | Free agent signing |
| Jan 28, 2004 | Signed as free agent | Steve Lomasney | — | Cincinnati Reds | Free agent signing |
| Jan 28, 2004 | Signed as free agent | Jim Parque | — | Arizona Diamondbacks | Free agent signing |
| Jan 28, 2004 | Signed as free agent | Ruben Quevedo | — | Baltimore Orioles | Free agent signing |
| Jan 27, 2004 | Signed as free agent | Ruben Mateo | — | Pittsburgh Pirates | Free agent signing |
| Jan 26, 2004 | Signed as free agent | Travis Chapman | — | Kansas City Royals | Free agent signing |
| Jan 26, 2004 | Signed as free agent | Karim Garcia | — | New York Mets | Free agent signing |
| Jan 26, 2004 | Signed as free agent | Jason Jimenez | — | Florida Marlins | Free agent signing |
| Jan 26, 2004 | Signed as free agent | Sidney Ponson | — | Baltimore Orioles | Free agent signing |
| Jan 26, 2004 | Signed as free agent | Paul Rigdon | — | Boston Red Sox | Free agent signing |
| Jan 26, 2004 | Signed as free agent | Oscar Salazar | — | Cleveland Indians | Free agent signing |
| Jan 26, 2004 | Signed as free agent | Scott Sheldon | — | Milwaukee Brewers | Free agent signing |
| Jan 26, 2004 | Signed as free agent | Rick White | — | Los Angeles Dodgers | Free agent signing |
| Jan 26, 2004 | Trade | Jaime Cerda | New York Mets | Kansas City Royals | Trade |
| Jan 26, 2004 | Trade | Shawn Sedlacek | Kansas City Royals | New York Mets | Trade |
| Jan 25, 2004 | Signed as free agent | Jed Hansen | — | Kansas City Royals | Free agent signing |
| Jan 24, 2004 | Signed as free agent | Jim Chamblee | — | Cincinnati Reds | Free agent signing |
| Jan 24, 2004 | Signed as free agent | Rey Ordonez | — | San Diego Padres | Free agent signing |
| Jan 24, 2004 | Signed as free agent | Robert Person | — | Chicago White Sox | Free agent signing |
| Jan 24, 2004 | Signed as free agent | Scott Randall | — | Cincinnati Reds | Free agent signing |
| Jan 24, 2004 | Signed as free agent | Rick Reed | — | Pittsburgh Pirates | Free agent signing |
| Jan 24, 2004 | Signed as free agent | Jermaine Van Buren | — | Chicago Cubs | Free agent signing |
| Jan 23, 2004 | Signed as free agent | Kevin Barker | — | Philadelphia Phillies | Free agent signing |
| Jan 23, 2004 | Signed as free agent | Pasqual Coco | — | Montreal Expos | Free agent signing |
| Jan 23, 2004 | Signed as free agent | Jeremy Giambi | — | Los Angeles Dodgers | Free agent signing |
| Jan 23, 2004 | Signed as free agent | Brian Powell | — | Philadelphia Phillies | Free agent signing |
| Jan 23, 2004 | Signed as free agent | Brandon Villafuerte | — | Arizona Diamondbacks | Free agent signing |
| Jan 22, 2004 | Signed as free agent | Luther Hackman | — | Cleveland Indians | Free agent signing |
| Jan 22, 2004 | Signed as free agent | Rick Helling | — | Minnesota Twins | Free agent signing |
| Jan 22, 2004 | Signed as free agent | Randy Knorr | — | Montreal Expos | Free agent signing |
| Jan 22, 2004 | Signed as free agent | Donaldo Mendez | — | Pittsburgh Pirates | Free agent signing |
| Jan 22, 2004 | Signed as free agent | Damian Moss | — | Tampa Bay Devil Rays | Free agent signing |
| Jan 22, 2004 | Signed as free agent | Calvin Murray | — | Chicago Cubs | Free agent signing |
| Jan 22, 2004 | Signed as free agent | Todd Ritchie | — | Tampa Bay Devil Rays | Free agent signing |
| Jan 22, 2004 | Signed as free agent | Brian Simmons | — | Minnesota Twins | Free agent signing |
| Jan 22, 2004 | Signed as free agent | Shingo Takatsu | — | Chicago White Sox | Free agent signing with first major-league team |
| Jan 22, 2004 | Signed as free agent | Matt Wise | — | Milwaukee Brewers | Free agent signing |
| Jan 22, 2004 | Signed as free agent | Steve Woodard | — | Oakland Athletics | Free agent signing |
| Jan 22, 2004 | Signed | Luis Garcia | — | Los Angeles Dodgers | Amateur free agent signing |
| Jan 21, 2004 | Signed as free agent | Marvin Benard | — | Chicago White Sox | Free agent signing |
| Jan 21, 2004 | Signed as free agent | Ivanon Coffie | — | Houston Astros | Free agent signing |
| Jan 21, 2004 | Signed as free agent | Jeff D'Amico | — | Cleveland Indians | Free agent signing |
| Jan 21, 2004 | Signed as free agent | Ryan Dempster | — | Chicago Cubs | Free agent signing |
| Jan 21, 2004 | Signed as free agent | David Doster | — | San Francisco Giants | Free agent signing |
| Jan 21, 2004 | Signed as free agent | Lou Merloni | — | Cleveland Indians | Free agent signing |
| Jan 21, 2004 | Signed as free agent | Larry Sutton | — | Florida Marlins | Free agent signing |
| Jan 21, 2004 | Signed as free agent | Turk Wendell | — | Colorado Rockies | Free agent signing |
| Jan 20, 2004 | Signed as free agent | Adrian Brown | — | Kansas City Royals | Free agent signing |
| Jan 20, 2004 | Signed as free agent | Sandy Martinez | — | Pittsburgh Pirates | Free agent signing |
| Jan 20, 2004 | Signed as free agent | Mike Matthews | — | Cincinnati Reds | Free agent signing |
| Jan 20, 2004 | Signed as free agent | Jose Parra | — | New York Mets | Free agent signing |
| Jan 20, 2004 | Signed as free agent | Willis Roberts | — | Pittsburgh Pirates | Free agent signing |
| Jan 20, 2004 | Signed as free agent | Glendon Rusch | — | Texas Rangers | Free agent signing |
| Jan 20, 2004 | Signed as free agent | Esteban Yan | — | Detroit Tigers | Free agent signing |
| Jan 19, 2004 | Signed as free agent | Roger Clemens | — | Houston Astros | Free agent signing |
| Jan 19, 2004 | Signed as free agent | Juan Diaz | — | Minnesota Twins | Free agent signing |
| Jan 19, 2004 | Signed as free agent | Mike Myers | — | Seattle Mariners | Free agent signing |
| Jan 19, 2004 | Signed as free agent | Keith Osik | — | Baltimore Orioles | Free agent signing |
| Jan 19, 2004 | Signed as free agent | Orlando Palmeiro | — | Houston Astros | Free agent signing |
| Jan 19, 2004 | Signed as free agent | Reggie Taylor | — | Cincinnati Reds | Free agent signing |
| Jan 18, 2004 | Signed as free agent | Emil Brown | — | St. Louis Cardinals | Free agent signing |
| Jan 18, 2004 | Signed as free agent | Mark Little | — | Cleveland Indians | Free agent signing |
| Jan 18, 2004 | Signed as free agent | Robert Machado | — | Baltimore Orioles | Free agent signing |
| Jan 18, 2004 | Signed as free agent | Ed Yarnall | — | Boston Red Sox | Free agent signing |
| Jan 17, 2004 | Signed as free agent | Mark Sweeney | — | Colorado Rockies | Free agent signing |
| Jan 16, 2004 | Signed as free agent | Nick Bierbrodt | — | Boston Red Sox | Free agent signing |
| Jan 16, 2004 | Signed as free agent | Matt Blank | — | Florida Marlins | Free agent signing |
| Jan 16, 2004 | Signed as free agent | Hiram Bocachica | — | Seattle Mariners | Free agent signing |
| Jan 16, 2004 | Signed as free agent | Kenny Kelly | — | New York Mets | Free agent signing |
| Jan 16, 2004 | Signed as free agent | Doug Linton | — | Kansas City Royals | Free agent signing |
| Jan 15, 2004 | Signed as free agent | Craig Dingman | — | Detroit Tigers | Free agent signing |
| Jan 15, 2004 | Signed as free agent | Courtney Duncan | — | Chicago White Sox | Free agent signing |
| Jan 15, 2004 | Signed as free agent | Shane Halter | — | Anaheim Angels | Free agent signing |
| Jan 15, 2004 | Signed as free agent | A. J. Hinch | — | Philadelphia Phillies | Free agent signing |
| Jan 15, 2004 | Signed as free agent | Damian Jackson | — | Colorado Rockies | Free agent signing |
| Jan 15, 2004 | Signed as free agent | Felix Martinez | — | Chicago Cubs | Free agent signing |
| Jan 15, 2004 | Signed as free agent | Josh Paul | — | Anaheim Angels | Free agent signing |
| Jan 14, 2004 | Signed as free agent | Hector Almonte | — | Pittsburgh Pirates | Free agent signing |
| Jan 14, 2004 | Signed as free agent | Brian Daubach | — | Boston Red Sox | Free agent signing |
| Jan 14, 2004 | Signed as free agent | Bobby Estalella | — | Detroit Tigers | Free agent signing |
| Jan 14, 2004 | Signed as free agent | Sal Fasano | — | New York Yankees | Free agent signing |
| Jan 14, 2004 | Signed as free agent | Jeff Fassero | — | Colorado Rockies | Free agent signing |
| Jan 14, 2004 | Signed as free agent | Vladimir Guerrero | — | Anaheim Angels | Free agent signing |
| Jan 14, 2004 | Signed as free agent | Jim Mann | — | New York Yankees | Free agent signing |
| Jan 14, 2004 | Signed as free agent | Jeff Nelson | — | Texas Rangers | Free agent signing |
| Jan 14, 2004 | Signed as free agent | Greg Norton | — | Detroit Tigers | Free agent signing |
| Jan 14, 2004 | Signed as free agent | Rafael Palmeiro | — | Baltimore Orioles | Free agent signing |
| Jan 14, 2004 | Signed as free agent | Kenny Rogers | — | Texas Rangers | Free agent signing |
| Jan 14, 2004 | Signed as free agent | John Vander Wal | — | Cincinnati Reds | Free agent signing |
| Jan 13, 2004 | Signed as free agent | Luke Allen | — | Pittsburgh Pirates | Free agent signing |
| Jan 13, 2004 | Signed as free agent | Eddie Oropesa | — | San Diego Padres | Free agent signing |
| Jan 13, 2004 | Signed as free agent | Hector Ortiz | — | Colorado Rockies | Free agent signing |
| Jan 13, 2004 | Signed as free agent | Jay Payton | — | San Diego Padres | Free agent signing |
| Jan 13, 2004 | Signed as free agent | Ben Petrick | — | Detroit Tigers | Free agent signing |
| Jan 13, 2004 | Released | Brandon Villafuerte | San Diego Padres | — | Release |
| Jan 13, 2004 | Signed as free agent | Mike Williams | — | Tampa Bay Devil Rays | Free agent signing |
| Jan 13, 2004 | Signed as free agent | Gregg Zaun | — | Montreal Expos | Free agent signing |
| Jan 12, 2004 | Signed as free agent | Winston Abreu | — | Los Angeles Dodgers | Free agent signing |
| Jan 12, 2004 | Signed as free agent | Rod Barajas | — | Texas Rangers | Free agent signing |
| Jan 12, 2004 | Signed as free agent | Scott Chiasson | — | Chicago Cubs | Free agent signing |
| Jan 12, 2004 | Signed as free agent | Tony Clark | — | New York Yankees | Free agent signing |
| Jan 12, 2004 | Signed as free agent | Wilson Delgado | — | St. Louis Cardinals | Free agent signing |
| Jan 12, 2004 | Signed as free agent | Luis Figueroa | — | Milwaukee Brewers | Free agent signing |
| Jan 12, 2004 | Signed as free agent | Julio Franco | — | Atlanta Braves | Free agent signing |
| Jan 12, 2004 | Signed as free agent | Todd Jones | — | Tampa Bay Devil Rays | Free agent signing |
| Jan 12, 2004 | Signed as free agent | Jason Karnuth | — | Detroit Tigers | Free agent signing |
| Jan 12, 2004 | Signed as free agent | Brian Mallette | — | Cincinnati Reds | Free agent signing |
| Jan 12, 2004 | Signed as free agent | Mitch Meluskey | — | Tampa Bay Devil Rays | Free agent signing |
| Jan 12, 2004 | Signed as free agent | Gabe Molina | — | Chicago Cubs | Free agent signing |
| Jan 12, 2004 | Signed as free agent | Randy Ruiz | — | St. Louis Cardinals | Free agent signing |
| Jan 12, 2004 | Signed as free agent | Brett Tomko | — | San Francisco Giants | Free agent signing |
| Jan 12, 2004 | Signed as free agent | Matt Whiteside | — | Atlanta Braves | Free agent signing |
| Jan 11, 2004 | Signed as free agent | Kris Keller | — | Chicago White Sox | Free agent signing |
| Jan 10, 2004 | Signed as free agent | Alan Benes | — | St. Louis Cardinals | Free agent signing |
| Jan 10, 2004 | Signed as free agent | Lou Collier | — | Philadelphia Phillies | Free agent signing |
| Jan 10, 2004 | Signed | Miguel Socolovich | — | Boston Red Sox | Amateur free agent signing |
| Jan 9, 2004 | Signed as free agent | Eliezer Alfonzo | — | Florida Marlins | Free agent signing |
| Jan 9, 2004 | Signed as free agent | Marlon Anderson | — | St. Louis Cardinals | Free agent signing |
| Jan 9, 2004 | Signed as free agent | Jeromy Burnitz | — | Colorado Rockies | Free agent signing |
| Jan 9, 2004 | Signed as free agent | Royce Clayton | — | Colorado Rockies | Free agent signing |
| Jan 9, 2004 | Signed as free agent | Robert Fick | — | Tampa Bay Devil Rays | Free agent signing |
| Jan 9, 2004 | Signed as free agent | Ryan Glynn | — | Atlanta Braves | Free agent signing |
| Jan 9, 2004 | Signed as free agent | Mike Lincoln | — | St. Louis Cardinals | Free agent signing |
| Jan 9, 2004 | Signed as free agent | Pablo Ozuna | — | Detroit Tigers | Free agent signing |
| Jan 9, 2004 | Signed as free agent | Luke Prokopec | — | Cincinnati Reds | Free agent signing |
| Jan 9, 2004 | Signed as free agent | Julian Tavarez | — | St. Louis Cardinals | Free agent signing |
| Jan 8, 2004 | Signed as free agent | Rich Aurilia | — | Seattle Mariners | Free agent signing |
| Jan 8, 2004 | Signed as free agent | Troy Brohawn | — | Los Angeles Dodgers | Free agent signing |
| Jan 8, 2004 | Signed as free agent | Mike DeJean | — | Baltimore Orioles | Free agent signing |
| Jan 8, 2004 | Signed as free agent | Micah Franklin | — | Chicago White Sox | Free agent signing |
| Jan 8, 2004 | Signed as free agent | Aaron Fultz | — | Minnesota Twins | Free agent signing |
| Jan 8, 2004 | Signed as free agent | Paul Hoover | — | Montreal Expos | Free agent signing |
| Jan 8, 2004 | Signed as free agent | Jose Jimenez | — | Cleveland Indians | Free agent signing |
| Jan 8, 2004 | Signed as free agent | Brian Jordan | — | Texas Rangers | Free agent signing |
| Jan 8, 2004 | Signed as free agent | Jeff Liefer | — | Milwaukee Brewers | Free agent signing |
| Jan 8, 2004 | Signed as free agent | Braden Looper | — | New York Mets | Free agent signing |
| Jan 8, 2004 | Signed as free agent | Luis Lopez | — | Montreal Expos | Free agent signing |
| Jan 8, 2004 | Signed as free agent | Lou Pote | — | St. Louis Cardinals | Free agent signing |
| Jan 8, 2004 | Signed as free agent | Britt Reames | — | Oakland Athletics | Free agent signing |
| Jan 8, 2004 | Signed as free agent | Carlos Reyes | — | Tampa Bay Devil Rays | Free agent signing |
| Jan 8, 2004 | Signed as free agent | Mike Romano | — | Atlanta Braves | Free agent signing |
| Jan 8, 2004 | Signed as free agent | Javier Valentin | — | Cincinnati Reds | Free agent signing |
| Jan 8, 2004 | Trade | Carlos Guillen | Seattle Mariners | Detroit Tigers | Trade |
| Jan 8, 2004 | Trade | Ramon Santiago | Detroit Tigers | Seattle Mariners | Trade |
| Jan 8, 2004 | Trade | Juan Gonzalez | Detroit Tigers | Seattle Mariners | Trade |
| Jan 7, 2004 | Signed as free agent | Terry Adams | — | Toronto Blue Jays | Free agent signing |
| Jan 7, 2004 | Signed as free agent | Juan Brito | — | Arizona Diamondbacks | Free agent signing |
| Jan 7, 2004 | Signed as free agent | Deivi Cruz | — | Tampa Bay Devil Rays | Free agent signing |
| Jan 7, 2004 | Signed as free agent | Brook Fordyce | — | Tampa Bay Devil Rays | Free agent signing |
| Jan 7, 2004 | Signed as free agent | Keith Foulke | — | Boston Red Sox | Free agent signing |
| Jan 7, 2004 | Signed as free agent | Chris Gomez | — | Toronto Blue Jays | Free agent signing |
| Jan 7, 2004 | Signed as free agent | Chad Hermansen | — | Toronto Blue Jays | Free agent signing |
| Jan 7, 2004 | Signed as free agent | Bob Howry | — | Cleveland Indians | Free agent signing |
| Jan 7, 2004 | Signed as free agent | Mark Lukasiewicz | — | Toronto Blue Jays | Free agent signing |
| Jan 7, 2004 | Signed as free agent | Trever Miller | — | Tampa Bay Devil Rays | Free agent signing |
| Jan 7, 2004 | Signed as free agent | Aaron Myette | — | Cincinnati Reds | Free agent signing |
| Jan 7, 2004 | Signed as free agent | Cliff Politte | — | Chicago White Sox | Free agent signing |
| Jan 7, 2004 | Signed as free agent | Chris Prieto | — | St. Louis Cardinals | Free agent signing |
| Jan 7, 2004 | Signed as free agent | Brandon Puffer | — | San Diego Padres | Free agent signing |
| Jan 7, 2004 | Signed as free agent | Julio Ramirez | — | Arizona Diamondbacks | Free agent signing |
| Jan 7, 2004 | Signed as free agent | Rodrigo Rosario | — | Houston Astros | Free agent signing |
| Jan 7, 2004 | Signed as free agent | Jared Sandberg | — | Tampa Bay Devil Rays | Free agent signing |
| Jan 7, 2004 | Signed as free agent | Blake Stein | — | Pittsburgh Pirates | Free agent signing |
| Jan 7, 2004 | Signed as free agent | Justin Thompson | — | Texas Rangers | Free agent signing |
| Jan 7, 2004 | Signed as free agent | Andy Tracy | — | Colorado Rockies | Free agent signing |
| Jan 7, 2004 | Signed as free agent | Andy Van Hekken | — | Detroit Tigers | Free agent signing |
| Jan 7, 2004 | Signed as free agent | Daryle Ward | — | Pittsburgh Pirates | Free agent signing |
| Jan 6, 2004 | Signed as free agent | Brent Abernathy | — | Detroit Tigers | Free agent signing |
| Jan 6, 2004 | Signed as free agent | Roberto Alomar | — | Arizona Diamondbacks | Free agent signing |
| Jan 6, 2004 | Signed as free agent | Danys Baez | — | Tampa Bay Devil Rays | Free agent signing |
| Jan 6, 2004 | Signed as free agent | Tony Batista | — | Montreal Expos | Free agent signing |
| Jan 6, 2004 | Signed as free agent | Armando Benitez | — | Florida Marlins | Free agent signing |
| Jan 6, 2004 | Signed as free agent | Toby Borland | — | Florida Marlins | Free agent signing |
| Jan 6, 2004 | Signed as free agent | Vic Darensbourg | — | Chicago White Sox | Free agent signing |
| Jan 6, 2004 | Signed as free agent | Tim Drew | — | Atlanta Braves | Free agent signing |
| Jan 6, 2004 | Signed as free agent | Juan Gonzalez | — | Kansas City Royals | Free agent signing |
| Jan 6, 2004 | Signed as free agent | Raul Gonzalez | — | New York Mets | Free agent signing |
| Jan 6, 2004 | Signed as free agent | Brandon Harper | — | Detroit Tigers | Free agent signing |
| Jan 6, 2004 | Signed as free agent | Erik Hiljus | — | Kansas City Royals | Free agent signing |
| Jan 6, 2004 | Signed as free agent | Jeremy Hill | — | New York Mets | Free agent signing |
| Jan 6, 2004 | Signed as free agent | Cory Lidle | — | Cincinnati Reds | Free agent signing |
| Jan 6, 2004 | Signed as free agent | Kenny Lofton | — | New York Yankees | Free agent signing |
| Jan 6, 2004 | Signed as free agent | Javy Lopez | — | Baltimore Orioles | Free agent signing |
| Jan 6, 2004 | Signed as free agent | Shane Reynolds | — | Arizona Diamondbacks | Free agent signing |
| Jan 6, 2004 | Signed as free agent | Rob Sasser | — | Chicago White Sox | Free agent signing |
| Jan 6, 2004 | Signed as free agent | Chuck Smith | — | Atlanta Braves | Free agent signing |
| Jan 6, 2004 | Signed as free agent | Steve Sparks | — | Arizona Diamondbacks | Free agent signing |
| Jan 6, 2004 | Signed as free agent | Chris Stynes | — | Pittsburgh Pirates | Free agent signing |
| Jan 6, 2004 | Signed as free agent | Fernando Tatis | — | Tampa Bay Devil Rays | Free agent signing |
| Jan 6, 2004 | Signed as free agent | Todd Walker | — | Chicago Cubs | Free agent signing |
| Jan 6, 2004 | Signed as free agent | David Wells | — | San Diego Padres | Free agent signing |
| Jan 6, 2004 | Signed as free agent | Eric Young | — | Texas Rangers | Free agent signing |
| Jan 6, 2004 | Trade | Unnamed | Seattle Mariners | San Diego Padres | $ |
| Jan 6, 2004 | Trade | Jeff Cirillo | Seattle Mariners | San Diego Padres | Trade |
| Jan 6, 2004 | Trade | Brian Sweeney | Seattle Mariners | San Diego Padres | Trade |
| Jan 6, 2004 | Trade | Kevin Jarvis | San Diego Padres | Seattle Mariners | Trade |
| Jan 6, 2004 | Trade | Wiki Gonzalez | San Diego Padres | Seattle Mariners | Trade |
| Jan 6, 2004 | Trade | Dave Hansen | San Diego Padres | Seattle Mariners | Trade |
| Jan 6, 2004 | Trade | Vince Faison | San Diego Padres | Seattle Mariners | Trade |
| Jan 5, 2004 | Released | Mike Fyhrie | Florida Marlins | — | Release |
| Jan 5, 2004 | Signed as free agent | Benji Gil | — | Colorado Rockies | Free agent signing |
| Jan 5, 2004 | Signed as free agent | Mike Holtz | — | Tampa Bay Devil Rays | Free agent signing |
| Jan 5, 2004 | Signed as free agent | Matt Miller | — | Cleveland Indians | Free agent signing |
| Jan 5, 2004 | Signed as free agent | Alberto Reyes | — | Tampa Bay Devil Rays | Free agent signing |
| Jan 5, 2004 | Signed as free agent | Bubba Trammell | — | Los Angeles Dodgers | Free agent signing |
| Jan 5, 2004 | Trade | Ryan Church | Cleveland Indians | Montreal Expos | Trade |
| Jan 5, 2004 | Trade | Maicer Izturis | Cleveland Indians | Montreal Expos | Trade |
| Jan 5, 2004 | Trade | Scott Stewart | Montreal Expos | Cleveland Indians | Trade |
| Jan 4, 2004 | Signed as free agent | Carl Sadler | — | Cleveland Indians | Free agent signing |
| Jan 3, 2004 | Signed as free agent | Jimmy Anderson | — | Chicago Cubs | Free agent signing |
| Jan 3, 2004 | Signed as free agent | Chris Singleton | — | Pittsburgh Pirates | Free agent signing |
| Jan 2, 2004 | Signed as free agent | Lenny Harris | — | Florida Marlins | Free agent signing |
| Jan 2, 2004 | Signed as free agent | Adrian Hernandez | — | Milwaukee Brewers | Free agent signing |
| Jan 2, 2004 | Signed as free agent | Olmedo Saenz | — | Los Angeles Dodgers | Free agent signing |
| Jan 2, 2004 | Signed as free agent | Kevin Tolar | — | Minnesota Twins | Free agent signing |
| Jan 2, 2004 | Signed as free agent | Chris Truby | — | Pittsburgh Pirates | Free agent signing |
| Jan 2, 2004 | Signed as free agent | Kris Wilson | — | Kansas City Royals | Free agent signing |
| Jan 1, 2004 | Signed as free agent | Jayson Durocher | — | Toronto Blue Jays | Free agent signing |
Every row is mapped onto the same trade / signing / release vocabulary the modern feed uses, with the era’s own type description kept on each row. Club names are the names of the day (the Boston Braves years, the Brooklyn Dodgers years), and each links to the franchise it is today. Some dates are only partially known or flagged approximate by the source; they are shown exactly as published, never completed to a fake precise day.