Here's an article I've been expecting for a year now because I'm a cynical, callous jerk.
I remember earlier this season when Trevor Cahill was striking out like 7.5 per 9, I had become concerned that I would have to swallow my pride and just admit that Cahill was some kind of BABIP controlling, strikeout inflating Jered Weaver starter kit who would only dash my expectations of his sort-of-barely-above averageness at every opportunity. Now, however, the only thing inflating is Cahill's BB/9 (a grotesque 4.01), and that unbelievable 2010 BABIP of .236 is suddenly a rising 2011 .278.
So where does this sort of normalization leave Cahill? Well, he is still striking out a batter more an inning this season over last year (5.40 to 6.55), so while he is walking the world at the moment, his FIP is nearly exactly the same as it was last season (4.18 to 4.19). If you dig a little deeper you'll notice that while Cahill's ground ball percentage has dropped a tad from last season from 56.0% to 54.8% but his fly ball percentage has dropped from 29.0% to 24.7 so he's still getting ground balls for an overwhelming majority of his outs. The trouble though, is his LD% has spiked from a career low 15.0% in 2010 to 20.4% here in 2011. So, some of those ground balls he induces are probably scooting past infielders when they weren't last season.
Which brings us to another factor, the A's defense. Last season the A's defense was one of the best in baseball with a 37.7 UZR and a major league best 74 Defensive Runs Saved. This season, however, so far, the A's haven't performed nearly as well with a third worst -14.5 UZR and only 6 DRS. For a pitcher like Cahill, who relies on getting ground balls, the more that get past his infield the more he might look to strike out hitters which could be contributing to that rising BB/9.
However, while I've wanted to gloat about this for months, it turns out that Cahill is, surprise, a good pitcher even with normal regression from his lofty 2010 heights, and probably one I shouldn't dismiss just because of bias and anger over the crazy success he has over the Rangers. It just so happens that, also surprise, he isn't a pitcher that can control, to a large extent, things like where the ball is hit once it leaves his hand at a more successful rate than any other pitcher of his skill set.
While Cahill hasn't gone complete 2010 Scott Feldman on baseball yet this season, it just goes to show that one historically great BABIP season doesn't mean such a rate is sustainable but also isn't everything we have to look when dissecting a pitcher who looks due for a slump. Now, if only the Rangers could figure him out.