One of the biggest success stories of the 2011 season has been Brandon McCarthy. From 2005-2009 he never posted an FIP better than 4.7, and twice had a FIP above 5. Then he spent 2010 injured and in the minors. But over 108 innings thus far this year, more than he has ever thrown in a season, he has a FIP of 2.69: a pretty incredible improvement. The immediate reasons are a big drop in walks — just 1.33 per nine fourth best for a pitcher this year with at least 100 innings — and an increase in ground balls. These improvements turned McCarthy from an average-control, fly-ball pitcher to an amazing-control, ground-ball pitcher, while not losing any of his strikeouts. That is going to lead to changes for the better — as it has for McCarthy.

Rob Neyer has a nice interview with McCarthy (which along with McCathry's great last start inspired this post), in which McCarthy discusses some of the adjustments he has made coming into this year. The main one was developing a fastball with more movement, and then the confidence that gave him. They also discuss McCarthy's injury history, which led him to average just 75 innings a year from 2005 to 2009. Kyle Boddy looked at pitchf/x data and film to examine mechanical changes McCarthy had made between 2009 and 2011. Boddy's mechanical analysis is always very interesting, this article is worth a read, and the upshot is that Boddy likes that changes that McCarthy has made, and that they may help him prevent injuries in the future.

So we know that McCarthy reworked his both his approach and mechanics heading into this season. Based on the pitchf/x data it also looks like he radically changed his pitching arsenal. McCarthy has all but abandoned his slider and change up; switched from mostly a four-seam to a mostly two-seam fastball; and added a cutter.

Before this year McCarthy's fastballs, which he threw around 65% of the time, were almost all four-seamers and were fly-ball pitches, getting just 31% grounders. Those have largely been replace by cutters and two-seam fastballs, which have ground-ball rates of 38% and 55% respectively. This explains his increase in grounders. He is also throwing the ball harder. His fastballs used to average 89 mph, but this year they average 91 mph. This is very surprising when going from predominately four-seam fastballs to two-seam fastballs, since two-seam fastballs tend to be slower. The change in mechanics look to have paid off.

Turning to his newfound command, here are the locations of his fastballs to right-handed batters in 2009 compared to his fastballs and cutters to right-handed batters in 2011:

As expected by his drop in walks McCarthy's pitch-level command is dramatically better. The pitches are in the zone more often, but more than that they cluster very tightly on the outside half of the strike zone. Meaning McCarthy is simultaneously better at pitching in the zone, but not in the down-and-in wheelhouse of right-handed batters.

Here are his fastballs in 2009 compared to his fastballs and cutters in 2011 to left-handed batters:

Again his pitches cluster much tighter in and around the strike zone in 2011. Interestingly he has gone inside more to lefties than he is to righties, the opposite of most right-hand pitchers. But it hasn't hurt him so far, as he has succeed against batters on both sides of the plate this year.

You really have to tip your hat to McCarthy, he seems to have completely retooled his arsenal for the better. With his two-seam fastball and cutter he has shown incredible command, while at the same time getting tons more ground balls (thanks mostly to the two-seam fastball) while not losing whiffs (thanks mostly to the cutter). He also has a very funny twitter account.