What is a Groundball Pitcher? Definition and Examples
A groundball pitcher is one who induces a high rate of ground balls on batted balls, typically above 50%, using sinkers, splitters, and low pitch location to keep the ball on the dirt.
What is a Groundball Pitcher?
A groundball pitcher is a pitcher whose batted-ball profile is dominated by ground balls — batted balls that hit the ground before reaching the outfield grass. The league-average ground-ball rate is roughly 42-44%, so a pitcher is generally considered a groundball pitcher when his ground-ball rate exceeds 50%. These pitchers are the opposite of fly-ball pitchers, who induce pop-ups and deep flies. Groundball pitchers are prized for their ability to limit extra-base hits, especially home runs, because a ground ball can never leave the yard.
The groundball pitcher is not a pitch type — it is a profile. The most common groundball pitches are sinkers, splitters, and changeups, which feature downward movement and are thrown low in the zone. The classic archetype is a power sinker-baller who attacks the bottom of the strike zone and induces weak contact on the ground. The modern groundball pitcher also relies on vertical approach angle — the angle at which the pitch crosses the plate — to keep the ball down.
How Groundball Rate is Measured
Ground-ball rate (GB%) is calculated as the percentage of a pitcher's batted-ball events (excluding strikeouts and walks) that are classified as ground balls. Statcast classifies batted balls into five categories: ground ball, line drive, fly ball, pop-up, and bunt. The formula is:
GB% = Ground Balls / (Ground Balls + Line Drives + Fly Balls + Pop-ups)
A ground ball is any batted ball with a launch angle between -50 and 10 degrees. Line drives are 10 to 25 degrees, fly balls are 25 to 50 degrees, and pop-ups are above 50 degrees. Statcast's classification is automated and uses the batted-ball's launch angle and trajectory.
Worked Example
In 2024, Logan Webb of the San Francisco Giants led MLB with a 60.4% ground-ball rate, the highest among qualified starters. Webb's primary weapon is a sinker that averaged 92.8 mph with 18.1 inches of induced vertical break — a pitch that dives toward the dirt. He threw his sinker 54% of the time, and batters pounded it into the ground at a 68% rate. Webb allowed just 0.62 home runs per nine innings, the fourth-lowest in baseball. By contrast, a fly-ball pitcher like Zac Gallen posted a 38% ground-ball rate and a 1.1 HR/9.
Why a Groundball Pitcher Matters
Groundball pitchers are the backbone of run prevention. Ground balls are singles at best, while fly balls can be doubles, triples, or home runs. The run expectancy of a ground ball is roughly 0.08 runs per batted ball, while a fly ball is 0.15 and a line drive is 0.35. A groundball pitcher with a 55% GB% suppresses slugging percentage and keeps the ball in the park.
For fantasy and DFS, groundball pitchers are valuable in pitcher-friendly parks and against teams with weak infield defenses. In real-world front offices, a groundball pitcher is a safer investment than a fly-ball pitcher because his home-run rate is more stable year-to-year. Groundball pitchers also pair well with elite infield defenses — a team with strong infielders can turn ground balls into outs at a much higher rate.
Limitations and Misconceptions
A groundball pitcher is not automatically a good pitcher — a ground ball through the infield is still a hit, and a pitcher with a 55% GB% but a 10% walk rate will struggle. Groundball pitchers also depend heavily on their defense: a poor infield turns ground balls into singles at a higher rate. A common misconception is that groundball pitchers cannot strike anyone out — many elite groundball pitchers like Webb, Corbin Burnes, and Framber Valdez also post strikeout rates above 25%. Groundball pitchers are also not immune to home runs — a sinker left up in the zone is a batting-practice fastball.
Related Terms
In Legends Deck
In Legends Deck, groundball pitchers receive a "GB% Rating" that directly reduces the probability of extra-base hits in the simulation. A pitcher with a 55%+ GB% gets a +4 bonus against home-run outcomes, while a pitcher with a 40% GB% is neutral. The sim also factors in the infield defense rating — a groundball pitcher on a team with elite infielders gets a further boost to his BABIP suppression.