I knew that I needed to write about AJ ever since this thought popped into my head: “Oh, AJ’s going to the Pirates? Well, he’s going to kill it over there.” Pause. Wait, really?
Well, the reason that semi-absurd thought crossed my mind had a lot to do with a couple articles (and some personal research) I have read about AJ’s park-controlled batted ball numbers. For example, Beyond the Boxscore took a look at 2011’s “unluckiest pitches” and ranked AJ’s four-seamer as the third unluckiest pitch in baseball; Michael Eder over at The Yankee Analysts (another fantastic Yankee site), wrote a piece about Burnett’s luck numbers, and compared him (favorably) to Tim Lincecum; and various other analysts have noted that his 2011 xFIP (3.86) was significantly lower than his 2011 ERA (5.15). It makes a little more sense in context, right? I mean, xFIP controls for park factors by removing the individual player’s HR/FB rate and inserting the league-average HR/FB rate (this is the only difference between xFIP and FIP). So, assuming that Yankee Stadium was responsible for at least some of his terrible 17.0% HR/FB, playing half his games at the more pitcher friendly PNC Park could really help him out.
Or at least that was my thinking.
To a certain extent, this is probably true, and AJ is due for a bounce-back year, especially when we consider his K/9 increased last year as compared to 2010 (up to 8.18 from 6.99), and his ground ball percent was higher than it has been since 2007 (he finished that season with the fascinating combination of a 3.75 ERA, a 4.33 FIP and a 3.51 xFIP, and had a hyper-high 17.7% HR/FB, which explains the drop in xFIP). His HR/FB rate was quite high in 2011, and should come down no matter where he plays, though I’ll get into this more in a bit.
When I talk about a “bounce-back year” for AJ, I’m really saying that if he continues with some of the positive peripheral numbers from 2011, he should fare slightly better in 2012; if he puts up his 2010 peripherals, he’ll probably stink.
But even if he continues putting up the same peripheral numbers, there are some things—and I mean outside of actually watching him (who does that anymore)—that make me think that he might just kinda suck (or at least not be able to change). The most glaringly obvious thing that I should point out is that he walked 3.92 batters per nine innings; in 2010 (his best year in terms of walks with the Yankees), he walked 3.76 per nine. These levels are unacceptable, even for AJ: he hadn’t had a complete season over 3.7 since 2002, when he walked 3.96 per nine.
Also, he was actually better at homer-prone Yankee Stadium than he was on the road. He struck people out more, walked people less, and averaged a better batting average against. (Caveat: he had a significantly higher BABIP away than at home, so this could explain some of the averages). He gave up home runs at a marginally faster rate (1.50 per nine, as opposed to 1.42 per nine), but actually had a lower HR/FB rate at home than away (16.8% to 17.4%).
Part of the (statistical) reason I’m not sold on an AJ comeback in Pittsburgh is that there’s part of me that thinks his—admittedly high—HR/FB rate is not just bad luck. He has consistently lost velocity on his fastball during his Yankee tenure (from an average of 94.2mph in 2009 to 92.7mph in 2011, though it dropped even more from 2007, when he averaged 95.9mph), and he has actually averaged a 13.08% HR/FB over the last six seasons, which is almost three points above the major league average. Admittedly, this is a part of the game over which he has little control—but I do think this shows you that AJ gets hit harder than you might otherwise expect.
This is why I don’t totally buy the predictive value of the xFIP numbers from 2011: remember, xFIP calculates FIP but inserts a league-average HR/FB rate (SIERA comes into similar trouble as xFIP in this regard). But that’s the problem: I don’t think we can expect a league average HR/FB rate from AJ. In fact, I’m more inclined to use other metrics to understand AJ’s 2011 season and look ahead to 2012, like good old FIP (he had a 4.77 FIP, only slightly better than his 2010 4.83). Another metric that makes sense in this scenario is true ERA or tERA, which was developed by my friend Graham MacAree (an ex-blogger at Lookout Landing and StatCorner, he now runs a fantastic Chelsea FC site) to improve on FIP and xFIP. Unlike xFIP, tERA incorporates (and actually emphasizes) batted ball data (and because of some of this, might be less predictive in some instances). AJ’s tERA was a whopping 5.15 in 2011, which is in the same ballpark as his 4.77 FIP (and, gasp, his 5.15 ERA).
To sum up (because this is getting too long): AJ might be due for a bounce-back year in 2012, especially if you believe that he’ll be able to drop his HR/FB rate down to league average. He was unlucky in 2011, but only to a degree—he was also very bad in some areas, and his velocity is dropping pretty quickly as he ages. While his 17.0% HR/FB is pretty high, it might not come down as far as one would expect, especially if we consider some other factors (his average HR/FB rate over his last few seasons, his dropping velocity, etc).
Overall, I’m not a huge AJ fan, and especially not for the Yankees. While he might bounce all the way up to a sub-4.00 ERA (as his 2011 xFIP might suggest), I find that pretty doubtful. However, if he were traded away from Yankee Stadium, I’d be more inclined to expect him to be a solid contributor, because another park might help him drop his HR/FB rate.