Let me present to you two pitchers:
Pitcher A: 372.2 IP, 4.56 ERA, 4.92 FIP, 4.89 xFIP, 6.1 K/9, 3.4 BB/9, 1.3 HR/9, 36.5% GB%
Pitcher B: 170.2 IP, 3.32 ERA, 2.86 FIP, 3.30 xFIP, 6.5 K/9, 1.3 BB/9, 0.6 HR/9, 46.7% GB%
From those two sets of numbers, they have very little in common. The strikeout rate is pretty close, but that's about it.
Oh, and they're the same guy.
Pitcher A is Brandon McCarthy pre-A's (2005-2009), and Pitcher B is McCarthy's 2011 season. It's a piece of evidence that suggests, "hey, if you increase your K/BB ratio from 1.8 to 4.9, that could make you a better pitcher." And while you're at it, make 12 percent of the balls put in play against you grounders instead of flyballs.In the interview that Nico transcribed and posted on Monday, when asked what was different about this past year, McCarthy said,
I think it's just confidence more than anything...When I got to the big leagues with the stuff that I had, I found that the margin for error is a lot shorter and it was really the first time in years that I had failed. And I don't think I handled it all that well: Just mentally I think it becomes a struggle, you start to nibble a bit more, you lose your confidence, and once you lose your confidence it's a hard thing to get back. So it really wasn't until I made wholesale changes that I think I got that confidence back, where "Screw it, I can throw this in the zone -- hit it, do anything you want to do with it and beat it into the ground."
Of course, most people don't just "have" confidence. It comes from somewhere; it's earned because of something they've changed, or some new result they're seeing. And I think McCarthy's comes from his fastball and its variations.
For the first part of his career, McCarthy was mostly fastball-changeup-curveball. Some of the Pitchf/x data shows he might have messed around with a slider, but that seems to be noise to me. The following data comes straight from FanGraphs.
| Season | Team | FB% | CB% | CH% | CT% |
| 2005 | White Sox | 61.1% (90.3) | 16.9% (76.2) | 21.9% (77.6) | |
| 2006 | White Sox | 63.4% (90.8) | 12.8% (76.3) | 21.8% (76.9) | |
| 2007 | Rangers | 65.9% (88.9) | 16.5% (75.6) | 17.6% (76.6) | |
| 2008 | Rangers | 65.7% (89.0) | 17.6% (75.5) | 16.8% (78.0) | |
| 2009 | Rangers | 64.9% (88.8) | 11.4% (77.1) | 11.0% (77.5) | |
| 2011 | Athletics | 42.0% (90.9) | 17.1% (79.8) | 2.3% (84.0) | 36.4% (90.2) |
While in Texas, McCarthy's velocity dropped slightly, and I'm sure some of that had to do with his injuries. In 2011, he basically eschewed changeups and threw two-thirds as many fastballs in favor of a cutter. I'm not sure if it's a new pitch, or if the pitch classifications changed, but based on the horizontal movement data, he was definitely doing something different. The cutter has about the same velocity as his fastball, but dives in to left-handed hitters.
If you look at the heat maps on the above-referenced FanGraphs' page, you'll see that McCarthy pounded left-handed hitters in all year, particularly with the fastball/cutter, something he hadn't done in the past. With the change in fastball type/addition of a cutter (whatever you want to call it), I would have expected to see McCarthy's numbers improve greatly against lefties. But not the case:
| Sample | TBF | BA | OBP | SLG |
| 2005-2009 vs. LHB | 756 | 0.251 | 0.336 | 0.428 |
| 2011 vs. LHB | 366 | 0.253 | 0.281 | 0.389 |
| 2005-2009 vs. RHB | 847 | 0.256 | 0.321 | 0.431 |
| 2011 vs. RHB | 324 | 0.253 | 0.281 | 0.349 |
I don't think that's enough to say anything definitive about his platoon split. He was significantly better against everyone. Of course, maybe we should just listen to him:
| Season | Team | Swing% | Contact% | Zone% |
| 2007 | Rangers | 44% | 82% | 50% |
| 2008 | Rangers | 43% | 84% | 50% |
| 2009 | Rangers | 43% | 85% | 53% |
| 2011 | Athletics | 50% | 84% | 59% |
Dude threw a lot more strikes and got a lot more outs. If a pitcher is not going to strike out a bunch of guys, he can't be walking a bunch either. Of course getting out of Chicago/Texas and into the Coliseum helped some, but if a pitcher has decent stuff, let them hit it. They're going to have to at some point if he's not taking care of hitters himself. And it's better with fewer guys on base, especially guys the pitcher has put there. Only took me 750 words to describe rocket science.
At the beginning article, I wrote "Oh, and they're the same guy." But maybe he isn't.
