BABIP – Batting Average on Balls in Play

BABIP or Batting Average on Balls in Play will measure how often a ball in play will be ruled a hit. A ball in play will either be a single, double, triple or an out. If a ball in play will be a hit has many factors not only the performance of the hitter. The pitcher, team defense and luck also play a factor in the outcome. League average is that around 30 % of balls in play will fall for a hit.

Implications for fantasy baseball

  • Sample size large enough?
  • Has the player made big changes in his playing style?
  • Compare BABIP to the players career BABIP not to league average
  • BABIP for hitters compared to pitchers require somewhat smaller sample size
  • Pitchers BABIP tend to be closer to league average over a career compared to a hitter

The formula

BABIP = (H – HR) / (AB – K – HR + SF)

In the numerator you will find hits minus home runs and in the denominator, you have at bats minus strikeouts, minus home runs and you add sacrifice flies back in.

BABIP – Batting average on balls in play

H – Hits

HR – Home runs

AB – At bats

K – Strikeouts

HR – Home runs

SF – Sacrifice flies

Influence factors

If you want to understand BABIP and use it you have to understand which factors influence the outcome. Usually we talk about the different factors in this aspect talent level, defense and luck.

  1. First talent level is apparent as a great hitter will probably get more hits. If you hit the ball harder it is more likely going to be a hit, compared to soft contact. As for a great pitcher he will likely have a little higher BABIP compared to a worse pitcher.
  2. If you take an at bat there are many factors that will influence if it will be a hit. The pitcher, the hitter but also defense. Defense has always been tricky to get good reliable stats from. But if you have a great defender on your team, with a big range it will be harder to get a hit. From the pitcher’s standpoint, a great defense behind you will surely help you to get better results from your pitches.
  3. Sometimes the hitter just gets great contact but hit it straight to the defender. Luck has something to do with the outcome, and is therefore something you consider when calculating and understanding BABIP.

Teams are more and more using shifts and if a certain player cannot prevent himself from constantly hitting into the shift he will more likely have a lower BABIP compared to the “average/standard” player.

What can you expect?

If you look for some kind of average BABIP for hitters you can say it is around .300. Some of the really good players can get up to around .350, and the less talented may be around .260. We can look at the leaderboard in the MLB in 2018 to get a wider perspective and some context.

MLB Top 10 in BABIP in 2018

  1. D. Martinez – Red Sox – .375
  2. Christian Yelich – Brewers – .373
  3. Mookie Betts – Red Sox – .368
  4. Mallex Smith – Rays – .366
  5. Nicholas Castellanos – Tigers – .361
  6. Paul Goldschmidt – Diamondbacks – .359
  7. Scooter Gennett – Reds – .358
  8. Freddie Freeman – Braves – .358
  9. Lorenzo Cain – Brewers – .357
  10. Matt Duffy – Rays – .353

BABIP for pitchers usually will be within .290 to .310. It will be tougher for pitchers to sustain a high BABIP.

League average BABIP – Hitters

  • 2018 – .296
  • 2017 – .300
  • 2016 – .300
  • 2015 – .299
  • 2014 – .299

League average BABIP – Pitchers

  • 2018 – .293
  • 2017 – .297
  • 2016 – .298
  • 2015 – .296
  • 2014 – .295

How to use BABIP

BABIP can be useful in evaluating players, but it is important you understand the limitations. First of all, you need to have large enough sample size. What is enough sample size? Well, we usually need to have just under 1,000 at bats (AB). It means you need to have at least two seasons of stats, therefor it can be tough to evaluate rookies solely on BABIP. Facing MLB pitching for the first time can be somewhat of a learning curve. For pitchers you of course also need to have enough sample size, around 1,000 balls in play. Otherwise you can not really draw any conclusion, because it will be too many factors to judge.

A common mistake made is if you look at a hitter you compare his current BABIP to the league average. If we assume the league average is .300 and you look at the current BABIP for one player .320 you blame it on luck. This would not be correct, because it is much better to look at his career BABIP and his stats the last couple of years. If he has not made any drastic changes to his swing look at the difference in BABIP for the same player. For pitchers it is more difficult to draw any conclusions for his BABIP the current season. This is simple because we need a larger sample size, and his stat line will be closer to league average. It is a major difference for pitchers compared to hitters.

If you evaluate a hitter it is wise to scout his playing style. Line drives will more often result in a hit compared to ground balls, and ground balls will more often be a hit compared to a flyball. If you know his playing style you can use it in your evaluation of the player.