Saturday, April 18, 2009

Fun with numbers: BAPIP

That's the American League average for BABIP (Batting Average on Balls in Play). The idea behind this stat is that everyone goes through stretches when everything off their bat goes straight to a fielder, and everyone goes through stretches when everything off their bat falls for a hit somewhere.

If a hitter's BAPIP is high, it means his ground balls are finding holes, his line drives are finding holes and his fly balls are finding holes. He's due for a step back. If a hitter's BAPIP is low, it means everything he's hitting is going straight to a fielder -- and he's due for some of those hits to start falling.

(As an example: In the second inning on Saturday, Mike Lowell ripped a line drive to left field with runners on second and third -- and it went straight to Felix Pie. Seven or eight times out of 10, a line drive hit that hard is going to get those runs home.)

Here are the BAPIP numbers for a few notable Red Sox hitters (through Friday):

* Kevin Youkilis: .469
You thought maybe he was going to hit .500 all season? You thought maybe it was all skill with no luck involved?

* Jason Bay: .333
It's higher than average, sure, but it's not so high that he can't keep hitting the way he's been hitting.

* Jacoby Ellsbury: .250
* Dustin Pedroia: .231
The top two in the Red Sox order have scuffled thus far; neither has a batting average above .235. But Pedroia has smoked some hits that defenders have made great plays on, and Ellsbury is a guy who should tend to have a high BAPIP because his speed will help him beat ouf some ground balls. Seeing low BAPIP numbers for both is a good sign -- it means their early-season slumps can be attributed more to bad luck than anything else.

* Mike Lowell: .226
The Red Sox are optimistic that their third baseman can bounce back from offseason hip surgery. He's hitting just .237 thus far, but a low BAPIP means he might be due for a couple of his line drives to fall.

* David Ortiz: .207
* Jason Varitek: .174
Here's the problem with BAPIP, though: It doesn't account for how hard you hit the ball. Some line drives into the outfield are going to get caught; some are going to fall for singles and doubles. But when you're hitting weak ground balls and pop-ups -- as both Varitek and Ortiz have been prone to do -- you're going to see fewer of your balls in play land for hits.


Fun With Numbers Bonus for all of those calling for Ortiz to be moved down in the batting order:

No, Big Papi isn't hitting the ball. He's off to a miserable start in terms of his results at the plate. But he's seeing 4.72 pitches per plate appearance thus far, by far the best total on the team. Part of that has to do with the fact that he's fouling more pitches off; that's what decreased bat speed will do to you.

But when he sees that many pitches every time he steps to the plate -- and he saw seven pitches en route to striking out in Saturday's first inning -- he's being at least a little bit productive.

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