Notes on Andrew Miller
June 16th, 2011 by czar

I’m thinking there’s got to be some correlation between BABIP, swinging strike rates both in and out of the zone, and LD rates that could give us a better idea of how much of the BABIP variation can be attributed to pitcher performance. It won’t help us in evaluating Miller today, since such data isn’t readily available in the minors. But the guy’s allowed only two HRs this year along with 9 doubles and 4 triples for an opponents’ SLG of .280 and a .099 ISO, so it seems he hasn’t been getting tattooed by gappers. In addition, 7 of those 15 XBH (and 11 of the 23 extra bases generated by them on 4 doubles, 2 triples and 1 HR) have come in just the past 3 games — during Miller’s 22/1 K/BB mastery. One might expect to see robust contact more frequently when a pitcher keeps virtually everything around the plate.

You can actually explain a huge amount of BABIP variance by just looking at batted ball profiles (so LD/GB/FB breakdown for example). All things considered equal, a pitcher who induces 10% less LD’s has a significantly lower “luck-normalized” BABIP (~xBABIP) since the BABIP for LD is something like ~0.710.

Unfortunately, without batted ball data in the minors, it’s tough to determine whether a drop in BABIP, from say .310 to .270, is luck-induced or the result of a pitcher having improved control/stuff. In Miller’s case it seems likely to be a little of both.

You’re just transferring the “this is a skill” assumption from BABIP to LD% when you do this. Yes line drives are more likely to be hits, but there isn’t a ton of data showing pitchers have major control over their line drive rates.

While it’s true that pitcher’s can be “lucky” with regard to batted ball profiles, they are still (at least moderately) well correlated on a year-to-year basis for individual pitchers (moreso than BABIP) which gives them more skill in explaining pitcher performance than blindly regressing BABIP alone.

Again, I’m NOT making this argument for Miller since we have no AAA batted ball data (well, without potentially parsing the game logs). I was just responding to mbd’s query of “how can we explain BABIP outside of just saying “every pitcher regresses to .300!”?”

Posted in Message Board Ramblings

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  • Traversing the land that is known as Red Sox Nation, The Czar Who Wears Red Sox is an attempt at compiling a repertoire of my ever-so-sexy forum posts (when I'm too lazy to write my own damn entry) and other random baseball thoughts that strike. For those whose posts serve as the inspiration of my epiphanies and rants, do not be angry, but merely, be honored that you have achieved such status. Names will never be revealed. Feedback appreciated, as this is a work in progress.

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