What is the Screwball? Definition and Examples
A screwball is a rare breaking pitch that moves opposite of a curveball — fading and dropping toward the pitcher's arm side — created by pronating the wrist outward at release rather than supinating it.
Plain-English Definition
The screwball is a "reverse curveball." Where a curveball thrown by a right-hander breaks down and to his glove side (toward a right-handed hitter's back foot), a right-handed screwball breaks down and to his arm side — running in on a righty hitter and away from a lefty. It's the only pitch in baseball that moves opposite of every other breaking ball in the right-hander's arsenal, which makes it devastatingly disorienting when thrown well. It's also nearly extinct in modern MLB — fewer than a half-dozen pitchers throw a true screwball in any given season — because of the unusual elbow stress and difficulty of teaching the release.
How the Screwball Is Thrown
A curveball is thrown by supinating the forearm — rotating the palm from facing the batter to facing the glove side, snapping the wrist downward and across the body. A screwball is thrown by doing the opposite: pronating the forearm so the palm rotates *outward* through release, with the middle finger pulling down and across the arm-side seam.
The mechanical result:
- Velocity: typically 75–85 mph — slower than the pitcher's fastball but faster than a curve
- Spin axis: roughly 9:00 to 10:30 on a clock face for a righty (mirror image of a slurve)
- Movement: 8–15 inches of arm-side run plus 4–8 inches of drop relative to a fastball trajectory
- Release: arm angle stays similar to the fastball; the difference is all in the wrist and forearm action
That pronation pattern is the same motion as a changeup — which is why most modern pitchers throw a circle change or vulcan change instead. They get screwball-shaped movement without the elbow torque of a true screwball release.
Worked Example
The most famous screwball artist in history is Carl Hubbell, who used it to win the 1933 NL MVP and once struck out Babe Ruth, Lou Gehrig, Jimmie Foxx, Al Simmons, and Joe Cronin consecutively in the 1934 All-Star Game. His arm pronated so severely from throwing the pitch that his left palm permanently faced outward when his arm hung at his side.
Fernando Valenzuela rode the screwball to the 1981 NL Rookie of the Year *and* Cy Young double — throwing it 30–40% of the time, mostly to right-handed hitters who couldn't track the inward run.
In the modern era, Brent Honeywell Jr. brought the pitch back as a top Rays prospect in the late 2010s, sitting 84–87 mph with 12+ inches of arm-side break. Héctor Santiago threw an occasional screwball in the mid-2010s. As of the 2025 season, virtually no MLB starter throws a true screwball with any frequency — the closest analogues are Devin Williams' "Airbender" changeup and Drew Rasmussen's pronated cutter, both of which mimic screwball movement without the classic grip and release.
Why the Screwball Matters
The screwball solves the platoon problem for left-on-right (or right-on-left) matchups. A right-handed pitcher's natural breaking ball runs away from a same-side hitter but spins toward an opposite-side hitter's barrel. A screwball reverses that — giving a righty a weapon that dives away from a lefty's bat. That's why historical screwballers have unusually flat platoon splits.
Limitations and Misconceptions
The screwball is not a splitter or a sinker, though all three produce arm-side movement. The screwball's distinguishing trait is active pronation through release, not just grip-induced fade. It's also widely believed to destroy elbows — the evidence is mixed; Valenzuela threw 250+ innings annually for years, but modern biomechanics labs measure higher medial elbow stress on the pitch than on most others.
Related Terms
In Legends Deck
Screwball is a tagged pitch type in Legends Deck's pitch arsenal system — extremely rare on modern cards, but a defining weapon on legacy cards like Hubbell, Valenzuela, and Christy Mathewson (whose "fadeaway" is the historical name for the same pitch). In-game, screwball cards neutralize the platoon penalty against opposite-handed hitters, giving them unique value in late-game matchup decisions.