What is a Groundball Single? Definition and Examples
A groundball single is a base hit that stays on the ground and reaches the outfield grass or finds a hole in the infield, typically with an exit velocity between 60 and 100 mph and a launch angle below 10 degrees.
What is a Groundball Single?
A groundball single is a base hit that never leaves the infield dirt — or barely reaches the outfield grass — and results in the batter reaching first base safely. These hits include slow rollers that die in the infield, sharp grounders that find a gap between infielders, and choppers that bounce over a fielder's head. Unlike bloop singles, groundball singles are often a product of a hitter's speed and bat control, not just luck.
How is a Groundball Single Measured?
Statcast categorizes batted balls by launch angle. A ground ball has a launch angle below 10 degrees. For a groundball single, the ball must:
- Have a launch angle between -15 and +10 degrees
- Result in a base hit
- Not be classified as a bunt (though bunts for hits are a subset)
Exit velocity for groundball singles ranges widely. A slow roller might leave the bat at 55 mph; a rocket through the infield can be 110 mph. The key variable is location: a ground ball hit directly at a fielder becomes an out; a ground ball hit into the shift gap or past a diving infielder becomes a single.
Statcast's xBA for groundballs is generally low — most ground balls become outs. The league-average xBA on groundballs is around .240, but that number rises to .400+ when the ball is hit to the opposite field or through the middle.
Worked Example
In 2023, Miami Marlins second baseman Luis Arraez led MLB with a .354 batting average. A significant portion of his hits were groundball singles. One representative hit came against the Chicago Cubs: Arraez hit a ground ball at 86.4 mph with a -4 degree launch angle toward the left side of the infield. The third baseman was playing deep, and the ball bounced past him into left field for a single. The xBA on that ball was .310 — a below-average outcome for a groundball, but Arraez's ability to place the ball away from defenders made it a hit.
By contrast, a 105 mph groundball single up the middle off the bat of Ronald Acuña Jr. had an xBA of .580 — a much more "deserved" hit because the velocity made it nearly impossible to field.
Why It Matters
Groundball singles are central to evaluating:
- Contact hitters: Hitters like Arraez, Steven Kwan, and Andres Gimenez build their offensive value on groundball singles. Their batting averages are real, but their power numbers are suppressed.
- Speed on the bases: A groundball single becomes a double when the runner steals second. Speed metrics like Sprint Speed correlate with the ability to beat out groundballs.
- Pitcher evaluation: Groundball pitchers like Marcus Stroman or Framber Valdez allow groundball singles but suppress home runs. A groundball single is a "cheap" hit — it scores fewer runs than a double or home run.
- Defensive metrics: Groundball singles are the batted-ball type most affected by defensive positioning. A groundball single through the shift is a failure of alignment, not necessarily a great piece of hitting.
Limitations and Common Misconceptions
The biggest misconception is that all groundball singles are "weak" contact. A 110 mph groundball through the infield is not weak — it is a rocket that the fielder simply cannot react to. Conversely, a 55 mph dribbler that dies in the grass is weak contact but still a hit.
Groundball singles are also not all created equal. Statcast's xBA separates them: a groundball single with an xBA of .600 is a well-struck ball; a groundball single with an xBA of .150 is a lucky roll. Hitters who consistently produce groundball singles with high xBA have real skill; hitters who rely on low-xBA groundballs are due for regression.
Groundball singles are often confused with infield singles. An infield single is a subset of groundball singles where the ball never leaves the infield. A groundball single that reaches the outfield grass is not an infield single — it is a "seeing-eye" single.
Related Terms
In Legends Deck
Groundball singles are a core outcome for Contact-focused cards in Legends Deck. A card with high Contact and low Power will generate groundball singles at a higher rate than a power hitter. Speed ratings also matter: a card with elite Sprint Speed converts more ground balls into infield singles. When building a lineup, a high-contact, high-speed leadoff hitter is the best profile for generating groundball singles and setting the table for power bats behind him.