Friday, April 16th, 2021

Baseball Statistics: BABIP

April 7, 2010 by  
Filed under Statistics and Analysis

On Monday, at a few minutes til 1pm, I sat down in front of my TV to root on my beloved Washington Nationals.  Unfortunately, the outcome of this game, like many others the Nats play in, didn’t go the way I had hoped.  They lost 11-1 to the Phillies.  Starting pitcher John Lannan didn’t survive the 4th inning and was replaced after giving up 7 hits and 5 earned runs. 

What I didn’t know was that Lannan’s performance both yesterday and historically is being studied by a group of baseball statisticians, or as insiders like to refer to them, Sabermetricians ( S-A-B-R being the acronym of the Society of American Baseball Research). You see, Lannan has an unusually low BABIP.  In fact, at .275, Lannan’s BABIP for 2008 and 2009 is the lowest in the majors!

What the devil is a BABIP?, you ask.  It is an acronym that stands for Batting Average on Balls in Play*.  The premise behind this statistic is that a pitcher cannot control what happens after a pitch is put into play and that luck is largely responsible for an unusually high or low BABIP.   Batter’s BABIP can fluctuate more wildly because some elite hitters have a propensity for line drives or some hitter’s fleet-footedness can cause likely outs into hits.  However, it is commonly held that a pitcher cannot do much to influence their BABIP.

The league average is somewhere between .290 and .300 and a pitcher whose BABIP is substantially higher than this, say .330, is said to be unlucky and, based on the law of large numbers, is likely to regress (i.e. improve) back toward the league average.   Conversely, if a pitcher’s BABIP is unusually low, say .275, (like Lannan’s) it is thought that they have been lucky and future performances will move back to the league average.

Given Lannan’s unusually low BABIP, the Sabermetricians are eagerly waiting to see if “regression to the mean” will occur and Lannan’s numbers will become more like the league average or is there something inherently different about Lannan’s pitched ball that makes batters have less success when they put his pitches into play. 

As the chart to the right indicates (Source:, Lannan’s changeup (CU) has a significantly lower BABIP than the league average.  Further breakdown, so detailed that it would take pages to explain, seems to indicate that, at least on his changeup, Lannan’s BABIP is more a manifestation of luck than skill.

There were a number of articles last year analyzing Lannan’s BABIP ..

and the blogosphere was abuzz or shall I say “atweet” about Monday’s performance against the Phils..

John Lannan’s Opening Day start, in light of some questions sabermetricians have asked about him for two years: #nats   from @masnBen

@masnBen #natsLannan had throw a strike in a teacup to get a called strike-put him behind in the count often. Halladay got more calls.  from @BooksonBaseball

(actually the second tweet is just me moaning about the umpiring of Monday’s game as if umpiring truly could have changed the outcome of a 11-1 rout)

What goes into a sustainably low BABIP?
There are a few different ingredients that make some pitchers induce batted balls that seem to find gloves. The most obvious ones are a low LD% and a high GB%. Line drives and ground balls are two more constants in baseball. Most line drives fall in for hits, while most ground balls don’t. It’s as simple as that. [Source: RotoExperts — FANTASY BASEBALL: TIPPING PITCHES, It’s all about the BABIP]

For now, though, we must wait and see if John Lannan is truly a statistical oddity or will he become “average”..BABIP speaking, that is.   Beyond these statistics, however, I can say with certainty that Lannan was quite average on Monday against the Phillies.  For that, I didn’t need a calculator; only my eyes.


*BABIP Calcualtion-  The Pitchers Formula for determining BABIP is: (hits allowed – home runs allowed) divided by (batters faced – home runs allowed – strike outs).  Home runs are subtracted in the equation, since it is not possible to make a defensive play on a ball that is hit into the stands.


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  1. […] UZR? BABIP? No doubt you have seen some recent articles, including on this website, using terms that sound like they could come directly from NASA or the CIA.  These […]

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