More Clay Buchholz and HR rates
June 22nd, 2011 by czar

So the difference between his 2.33 ERA last year and 3.48 ERA this year? Simply the fact that he’s giving up a ton of more homeruns than last year. HR/FB rate up to 10.1% from 5.6% last season. He’s already given up 1 more homerun (10 to 9) than all of last season in 90 less innings. So he’s essentially been the same pitcher, with an improved K and BB rate, just not as lucky in the HR department. Found these numbers interesting and thought I’d share.

Not to be overly nitpicky, but these are cumulative numbers. He really HASN’T been the same pitcher in 2011, oddly enough. I covered this a couple times before his injury, but since the beginning of May, Buchholz is (peripherally) on the best 50+ IP stretch of his career.

Buchholz – 2011 Peripheral Splits

Before 5/1 27 5 5.3 0.9 2 1.85 6.52 5.44
After 5/1 55.2 7.3 2.4 3 0.7 1.03 3.2 3.4

We’re still really, really nibbling around iffy sample sizes here, but the benefit of hindsight shows us his current string of fantastic starts is being offset by a horrendous first few starts to the season when you just look at his 2011 totals (all 82.2 IP). Assuming he is more like the May/June pitcher going forward (this may be up for debate given the fact that we are dissecting < 100 IP), we should see more and more separation between 2010 peripherals (like the ones you posted above) and 2011 as time goes on.

Can anyone speak to whether or not one can be “lucky in the homerun department?” I would consider the ability to keep a hitter from squaring up a ball and knocking out of the park a skill, not an issue of luck. See the difference between say, Ricky Nolasco and Greg Maddux. One has better stuff but gets hit a lot harder and the other is a Hall of Famer.

xFIP is just really FIP but instead of having #HR in the formula you put in [ FB% * (HR%/FB%) ] where the former is the pitchers actual FB% and the latter is a constant for flyballs (independent of pitcher) in ballpark X. Studies have shown xFIP is a better predictor of ERA than FIP, so logically there is a degree of luck to HR/FB that isn’t adequately captured by FIP. Essentially, you can argue that since the number of HRs in any given season is pretty small, rates are prone to wild swings depending on which side of the fence “just enough” or “just not enough” flies fall.

This is only saying pitchers may experience at least some “luck” in their HR/FB rates, NOT the total number of HR given up (which is where you’d obviously see difference between good and bad pitchers). I (personally) believe that pitchers probably can exert SOME control over HR/FB rates, but to my knowledge, no one has attempted to document whether or not that’s true. Regardless, it seems unlikely that that would be the dominant control over HR/FB given the fact that xFIP exists (and is a better predictor of ERA than non-normalized predictors) to begin with.

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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