We are reader supported. When you purchase through links on our site, we may earn an affiliate commission. Also, as an Amazon affiliate, we earn from qualifying purchases.
BABIP has become a widely used baseball statistic these days, but if you’ve never heard of it before, you might be wondering what exactly BABIP stands for and why it is so important.
BABIP stands for Batting Average on Balls In Play. It measures how often batted balls hit into the field of play result in hits rather than outs. It is calculated by dividing all hits minus home runs by all at-bats plus sacrifice flies minus strikeouts and home runs.
The formula looks like this: BABIP = (Hits – Home Runs)/(At-Bats + Sacrifice Flies – Strikeouts – Home Runs). Some calculations also subtract sacrifice bunts from the denominator.
The numerator is hits minus home runs because BABIP only measures how many hits a batter gets or a pitcher allows on balls in play. Home runs are balls that land beyond the outfield fence, and therefore outside the field of play.
The denominator is at-bats plus sacrifice flies minus strikeouts and home run because it is meant to encapsulate all at-bats in which the ball was put in play. The ball does not end up in play on home runs or strikeouts, but it does end up in play on sacrifice flies.
If a batter has a .300 BABIP, it means 30% of balls the batter put into play were hits. If a pitcher has a .300 BABIP, it means 30% of balls put into play against the pitcher were hits.
Why Is BABIP Useful?
BABIP is a tool to provide a deeper understanding of a player’s performance in other statistical areas. It should not be used to evaluate a player on its own.
For hitters, BABIP can be used to better understand their batting average and other statistics that incorporate batting average, such as slugging percentage and on-base percentage. For pitchers, it can be used to better understand the amount of hits they allow and, therefore, the amount of runs they allow, because hits often lead to runs.
Neither pitchers nor hitters have control over what happens to a batted ball after it is put into play. Once the batter has made contact with the ball, only the fielders can control whether or not it becomes a hit.
There is also an element of luck involved when it comes to balls in play — sometimes a batted ball is hit right at a fielder, other times it lands far away from any fielders. Neither hitters nor pitchers have very much control over the exact direction the ball is hit or where the fielders will be standing at any given moment.
If a player has a lower BABIP than they typically do, it suggests the defense has been making more plays than usual on the player’s batted balls — either because of good fielding or good luck. If a player has a higher BABIP than usual, the opposite is true.
Thus, BABIP is a good indicator of whether or not a player will continue to perform at a certain level going forward. If a hitter has a higher-than-usual batting average but also a higher-than-usual BABIP, there is a good chance the hitter’s batting average will not stay so high for much longer. Similarly, if a pitcher has a lower-than-usual ERA but also a lower-than-usual BABIP, there is a good chance the pitcher’s ERA will soon go up.
What Is Considered A Good BABIP In Baseball?
The league average BABIP in Major League Baseball these days is usually between .292 and .300. A good hitter typically has an above-average BABIP, while a poor hitter usually has a below-average BABIP. The best hitters in the league might regularly have a BABIP as high as .350, while the worst hitters will have a BABIP as low as .260.
For a pitcher, it is better to have a low BABIP, although most pitchers tend to maintain a BABIP very close to league average. That being said, some of the best pitchers can regularly record a BABIP as low as .270 or as high as .310.
How BABIP Is Used Differently For Hitters And Pitchers
BABIP can be used to evaluate both pitchers and hitters. However, it is used slightly differently for each.
When it comes to hitters, it is most helpful to look at their career BABIP. If over a period of time, a hitter has a BABIP higher than their career average, there is a good chance the hitter has been having good luck on balls in play. Eventually, it is likely the hitter’s BABIP will regress towards their career average, and their batting average will drop along with it.
Similarly, if a hitter has a BABIP lower than their career average, there is a good chance the hitter has been having bad luck on balls in play. With time, it is likely their BABIP will rise towards their career average, and so their batting average will rise too.
As for pitchers, it more helpful to compare a pitcher’s BABIP to the league average rather than the pitcher’s own career average. If a pitcher is allowing a higher BABIP than league average, the pitcher is probably having bad luck on balls in play. If they are allowing a lower BABIP than league average, there is a strong chance they are having good luck on balls in play.
What Counts As A Ball In Play?
A ball in play is any ball the batter makes contact with that does not immediately result in a dead ball. Thus, a home run and a foul ball do not count as balls in play because in both of those instances the ball is ruled dead as soon as it hits the ground.
A ground out, a fly out, a line out, a pop out, and a hit are all examples of balls in play.
Do Foul Balls Ever Count As Balls In Play?
If a ball lands in foul territory it is not considered to be in play. The ball is ruled dead and play is paused until the umpire resumes the game.
However, if a fielder catches a ball in foul territory before it hits the ground, it will be ruled a catch and the batter will be called out. The ball is not dead and the game will not be paused. In this case, because the ball is still considered live, such a batted ball is considered a ball in play.
Why Are Sacrifice Bunts Only Sometimes Considered Balls In Play?
FanGraphs is one of the baseball research websites that popularized BABIP. The FanGraphs formula does not consider sacrifice bunts balls to be in play. However, other popular baseball statistics databases, such as Baseball Reference, do consider sacrifice bunts to be balls in play.
According to FanGraphs, this is not because of a fundamental disagreement as to what counts as a ball in play, but simply a computing difficulty.
Ultimately, sacrifice bunts are rather uncommon, so it does not make a big difference whether or not they count as balls in play for the purpose of calculating BABIP.
What Other Statistics Can Show If A Player Has Had Good Or Bad Luck?
BABIP is one of many statistics that can be used to gain a deeper understanding of a player’s statistical profile. Other such stats include left on base percentage (LOB%), home run to fly ball ratio (HR/FB), ERA estimators (such as FIP and SIERA), and expected statistics (such as xwOBA).
Why Are Sacrifice Flies Not Considered At-Bats?
At-bats are meant to measure every time a batter has the opportunity to get a hit. Therefore, if a batter is walked or hit by pitch, the plate appearance does not count as an at-bat. Sacrifice flies and sacrifice bunts do not count as at-bats, because in these instances, a player is said to have “sacrificed” their opportunity to get a hit for the betterment of their team.