“How could you do this to me…AGAIN!!!” / US PRESSWIRE

Here’s a very quick look at some statistical explanations for why Jon Lester‘s 2012 season isn’t going so well.

First, here’s a look at his basic numbers. Lester posted 4 strong seasons from 2008 to 2011. Here’s a quick comparison of some stats:

Stat     2008-11     2012
K/9       8.7         7.6
H/9       8.0        10.0
WHIP      1.241       1.393
BB/9      3.2         2.6
HR/9      0.8         0.9

With fewer strikeouts and walks (and a similar rate of homers), batters against Lester are putting more balls in play. We’ll get to the “why” of that in a minute, but let’s see what the repercussions are.

Over 2008-2011, with runners in scoring position, Lester allowed a line of .225/.300/.351. So far in 2012, that same line is .267/.322/.543. That’s a lot more hits, and a lot more for extra bases.

Lester’s overall BAbip (batting average on balls put in play) is up this year, at .331 compared to .298 over the 08-11 period. With runners in scoring position, over 08-11, the BAbip was .270. This year in those situations, it’s .265, very slightly better.

So it would seem that Lester’s allowing more balls to be put in play, which even with an identical BAbip would mean more hits, and especially without runners in scoring position he’s allowing a lot more base knocks.

For the why, part, we can get a clue from Fangraph’s PitchFX data. Lester’s throwing a ton of sinkers this year, a pitch he started throwing only in 2010 and that he’s throwing about twice more often in 2012 than in the 2 years prior. Those pitches primarily used to be cut fastballs or straightup fastballs. His fastball, too, has lost some pep. At its peak in 2008-2009, his fastball averaged 93.5 MPH; in 2012 it’s down to 92.2 MPH.

What exactly is going on? I’d have to dig deeper to know for sure, but it’s clear that he’s not the same guy he was, and it’s not all down to bad luck.


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