The Mockingbird

A different look at BABIP

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Boy, I had no idea there was such hate out there for BABIP. I’ve gotten some emails that even made it sound like I actually discovered something new here, when I was really just trying to tell the mainstream to go re-read their SABR manual. I do have something else to add that has been rolling around in my head for ages, and it’s about BABIP for pitchers. Warning: it’s pretty spacey. And very nerdy. I’ll have some wacky photoshopped pictures of Bautista’s head on someone else’s body next week, I promise.

The problem

There was an outcry when it was discovered that BABIP was essentially the same for all pitchers. McCracken’s statement that: “there is little if any difference among major-league pitchers in their ability to prevent hits on balls hit in the field of play” simply made no sense to baseball minds.

Although that statement has been softened over the years (we now know that the ability is just very, very, small, and almost impossible to see through all the luck), it’s still deeply troubling. This is because it implies that the ball comes off the bat on a dirty slider on the outside corner is just as good as on a slow fastball down the middle. Pitchers can only hit, or miss, bats – otherwise it’s all the same. Pitching to contact does not exist.

That makes no intuitive sense, and even less if you’ve ever tried to hit a 90-mph fastball. If some major league pitcher was facing a team full of me’s, it’s obvious he would have a really low BABIP as I dribbled the occasional ball back to the mound and popped up a few (in addition to putting Pizza Pizza out of business). Ok, I’m an absurdly low-talent example, but the variety in quality of swings and pitches to hit in baseball is pretty wide, too. All contact can’t be the same.

And it isn’t. Different counts show different BABIP’s. Different locations, too. Breaking pitches each have  different BABIP‘s. So why wouldn’t a pitcher who threw more breaking balls have a consistently and significantly lower BABIP? Or one with significantly better control? And how do all these different numbers in different situations possibly even out to be the same for everyone?

Important realization #1

At least to some extent, the reason is that these factors are in balance. Throw tons of sliders, or pitch to the corners, and on those pitches you’re going to get weaker contact (i.e. a lower BABIP). But you’re also going to fall behind in the count more often and have to come in with a fastball down the middle, which will be hit harder (and thus for a higher BABIP).

Conversely, if you’re pounding the zone with fastballs, you’re going to give up more hits because that’s fastballs do, but you’re also going to be getting ahead more often, since they’re easier to control. (And the closer to down the middle you aim them, the more hits you give up, but the more often you get ahead). The advantage of being ahead in the count will balance to some degree disadvantage of throwing pitches that are more hittable.

A good example is a guy like Jesse Carlson, who broke into the league throwing more sliders than anyone else in the league (Fangraphs says 56%, pitch f/x says higher), and maintained a .230 BABIP over his first season. His second time around the league made the adjustment and stopped swinging at so many his sliders, meaning he was constantly working from behind against guys sitting fastball. He went through a really tough time, and then adjusted. He is a far more normal pitcher now, with a normal BABIP.


Maybe why everyone’s BABIP is similar that it is the “golden mean” for how much you should nibble, how much of the plate you should on average be catching. If your BABIP goes below league average, that means your stuff is nasty enough that you should be challenging hitters more, and getting more strikeouts at the expense of a little BABIP. If it goes way above, you’re finding too much of the plate and should work the corners or throw a ball once in a while, even if it means your walk rate goes up a little.

My big shiny idea is that (underneath the mighty wallop of luck that runs through it) the reason pitchers see a very consistent BABIP is not that “all balls in play are the same”, but because the optimal level of aggression in pitching for most pitchers — neither getting ahead too often or too little — results in a BABIP of that value.


1) Imagine a pitcher whose BABIP happens to be exactly .300. Lets say we teach him a slider he can only throw once in an at-bat — but it’s the best slider in existence! Guys just can’t touch it, and when they do, they only manage a .100 BABIP off it. But our imaginary pitcher is an idiot, so he throws it only on the first pitch of an at-bat. As a result, his BABIP goes down, and statisticians everywhere say that he’s been getting really lucky.

But then his catcher and pitching coach have a long talk with him, and convince him that he’s got to start using this thing for better use – punching guys out. It’s going to be a lot better if he can get guaranteed outs rather than guaranteed first strikes. So he starts throwing it on 0-2, and punches out a whole bunch of guys who were behind in the count and more likely to put the ball in play weakly — so his BABIP starts going back up, as his nastiness is correctly being converted into a much better result: maximum strikeouts. See! We say, he stopped getting lucky!

2) Now take another guy who of a sudden becomes incredibly hittable. He is overnight Joshified (Towerized?), and as you would expect, his BABIP goes way up as hitters start gearing up and crushing the ball off him, over the wall, etc. Statheads scream “how unlucky!” (As we did in 2004, when Josh Towers put together one of the worst seasons in baseball, but had a BABIP of .341). After a barrage of towering upper-deck shots, he will almost certainly become more fine: picking out the corners and throwing more junk, effective or not, will lower his BABIP (at the expense of some walks). And since he can’t quite finish guys off as well he used to with his weakened repertoire, what used to be K’s on 0-2 now result in the kind of weak contact you get on 0-2 lowering his BABIP further (although not necessarily making him any better). “It’s starting to even out!”, we cry…

I don’t know exactly how much this is happening, but it’s almost certainly part of the answer. Otherwise, pitch f/x analysis tells us electric stuff would mean lower BABIP, just as you would expect.

Possible ramifications

Once again, the real excitement is hit f/x, which will make this look like child’s play. But it’s possible that we could use BABIP to understand when a pitcher is catching too much of the plate or working around hitters too often. Although obviously only to some extent, because there’s still so much luck. But think about a 2008 Matsuzaka. He had a really low BABIP, and I think a lot of baseball experts, or anyone who watched his games, felt like he was underperforming in some ways for his stuff, because he pitched in such an odd, backwards, not MLB optimal BABIP style (and a .258 BABIP).

Or Roy Halladay. There were a few seasons when he was almost certainly “pitching to contact” because because of concerns about his arm. In 2005 and 2006, he had a BABIP of .262, and .276. There’s no way that was a coincidence, or an unmaintainable result. He struck out about one less a game, and just by watching him pitch you know why his K rate was so low and his GB rate so high – he’d get guys to 0-2 and throw a third sinking fastball, stuff like that. The use of his power curve dropped dramatically. And the truth is, he wasn’t as effective – his ERA+ dipped to 143 and then 121. Sometimes those 0-2 tappers would go through.

Now the doc is back to converting those weak 0-2 grounders into K’s again, and his overall numbers have increased dramatically (up to a 165 ERA+) over the last three years, while his BABIP has stopped being abnormally low. I would suggest that he was negatively affecting his results by pitching too aggressively, and has now returned to optimal.


A possible alternative (or at least a contributing factor) to the reason that pitchers don’t have widely different BABIP’s being that they have extremely low “ability” to affect what happens to balls in play is that deviating from the norm, or the perfect balance between contact, walks, and K’s eventually interferes negatively with your results, and is therefore weeded out, or corrected by major league pitchers. It may be possible to peer through the randomness involved in BABIP in order to use it to make general statistical statements about pitchers being too straightforward, or too crafty for their own good.

Written by halejon

February 10, 2011 at 1:08 am

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