Brandon McCarthy’s New Repertoire

Last night Brandon McCarthy started the home opener for the Diamondbacks. He pitched six and two-thirds innings, giving up six hits and five earned runs. Not the result he hoped for, but there were interesting changes I want to note. One start is too small of a sample size to draw any statistical conclusions, but we can see a change in a pitcher’s mindset via pitch selection.

Last year, McCarthy primarily threw four pitches: sinker, cutter, curveball, and changeup. (He threw a handful of four-seam fastballs last night, but that was a new development and the sample size is too small to allow me to say anything about it. It’s something to keep an eye on as the season progresses.) McCarthy used to throw a changeup early in his career, but he changed his mechanics after the 2010 season and moved away from the pitch. He added the changeup again in 2013, knowing that he could use one. So McCarthy worked on the changeup in early spring training, and began throwing it in games almost five percent of the time. But it seems like it’s gone again. The quotes in that article don’t explicitly say that the changeup was scrapped, but last night it was not thrown at all. When our Ryan P. Morrison talked to McCarthy three weeks ago, he confirmed that the changeup has been scrapped completely. It’s possible the coaching staff had some involvement in this decision as well.

McCarthy also used his cutter significantly less often than usual last night. Again, bear in mind that it’s only one start, but the difference is astounding. In 2013, he threw his cutter 34.6% of the time. Last night? He threw only six. That comes out to just around six percent of the time.

Why did decide to get rid of these two pitches specifically? He might be more confident in his sinker and curveball compared to the cutter and changeup. I wanted to look at the results to see if they back up this idea.Here’s the line drive rate per balls in play for the pitches in the last few years.

The changeup and cutter had significantly higher line drive rates than the other two pitches last year. To put it in context, the average LD% is 21.2. Line drives are bad. They go for hits more often than other types of batted balls. Okay, now you might be thinking, how about the fly ball rate? Well, here it is:

Again, far and away the two worst pitches were the changeup and the cutter. The average FB% was 34.3. This must have been a point of emphasis for McCarthy 2013 featured his highest home run/fly ball ratio since 2006.

It seems like McCarthy wants to rely heavily on the sinker and curve, with the occasional cutter and four-seam fastball mixed in. Time will tell if the new mix leads to different results.