Brandon McCarthy PITCHf/x: Sliders, Curves, and Slurves

News broke late this winter that Texas Rangers RHP Brandon McCarthy would be experimenting with a slurve, a pitch half-way between a slider and a curveball. It was later confirmed that this pitch was intended to replace McCarthy's curveball. I had always believed his curveball was a plus, so this news left me confused.

Yesterday afternoon, Brandon McCarthy debuted his new slurve against Cleveland and PITCHf/x was ready to go. On television, the new pitch didn't look that new, seemingly just a little harder with a little bit sharper break, and more than one person wondered if McCarthy was throwing both a slider and a curve ball.

I grabbed the PITCHf/x data from yesterday's game (April 9, 2009), and decided to compare it with a similar outing. I settled on McCarthy's April 9, 2007 start at home against Tampa Bay. In each start, PITCHf/x identified 4 different pitch types: fastball, curveball, slider, and change up. PITCHf/x data is never perfect, but there's still a lot of great information.

Let's first compare his release points from the catcher's perspective.

Brandon McCarthy's April 9, 2007 pitch release points.Brandon McCarthy's April 9, 2009 pitch release points.

At first glance, it appears that McCarthy's release point has moved about 6 to 10 inches toward third base in the past two years. While definitely interesting, this may or may not actually be the case. In 2007, release points were measured at 55 feet from the back corner of home plate, but the 2009 release points were measured at 50 feet from the back corner of home plate.

Taking a bit of a deeper look reveals that McCarthy's release of his change up is very consistent with that of his fastball with a few stragglers straying up a couple of inches. In 2007, McCarthy's curveball release was a little higher and a little closer to first base, but in 2009, his curveball/slider release is noticeably higher but directly above his fastball release.

Take a look at the pitch movement scatter plots below. Vertical movement is calculated compared to gravity - an approximation of the Magnus effect. This means that zero vertical movement is equal to gravity's effect, while a negative number drops more than gravity and a positive number drops less than gravity.

Brandon McCarthy's April 9, 2007 pitch movement.Brandon McCarthy's April 9, 2009 pitch movement.

Based on the PITCHf/x data shown in the graph, McCarthy's slurve is measurably different from his 2007 curveball. To further illustrate the difference, I grabbed velocity data for the two pitches as well. His average curveball velocity in the 2007 game was 73.47 mph, and his average slurve velocity in the 2009 game was 79.81 mph.

The most important difference between the old curveball and the new slurve is pretty simple: control. In the 2007 game, McCarthy threw 40% (10/25) of his curveballs for strikes. In the 2009 game, McCarthy threw 75% (15/20) of his slurves for strikes.

Yesterday, McCarthy threw 10 of 13 change ups for strikes. He had outstanding overall command of his off-speed stuff, but he really struggled with his fastball command, throwing only 34 of 60 (56.7%) for strikes.

I've noted this in the past, and it's still a major issue. McCarthy has a tendency to drag his arm behind his body when he throws his fastball. This is usually caused when the front shoulder "flies open" by turning toward home plate before the arm is ready to throw. The pitching arm tries to play catch up, but pitches usually wind up high and a tick or two slower when this happens.

In the 3rd inning, pitching coach Mike Maddux trotted out to chat with McCarthy. When he left, McCarthy's fastball jumped from 86-90 to 89-92 for his last 2.1 innings, and he was throwing it down in the zone. PITCHf/x is missing 5 pitches in this span, but after the visit, McCarthy rattled off 10 strikes on his next 12 fastballs.

Outside of that stretch, McCarthy threw only 50% strikes with his fastball. On the up side, Maddux appears to be on top of this, and I expect improvement in this aspect of McCarthy's game throughout the season.

Here are some quick shots:

  • In the 2007 game, McCarthy's fastball was 10" to 15" above gravity, and his curveball was 8" to 13" inches below gravity. That's a visual 18" to 28" of vertical separation between the two pitches. I don't have a comparison ready, but that's a huge difference.
  • McCarthy's fastball is straighter than ever. He's getting better back-spin, so the ball might appear to rise more, but his fastballs are all clustered around zero horizontal movement. In the 2007 game, he was getting a lot more arm-side movement.
  • McCarthy is a tall guy, but it's pretty crazy that he lets go of the baseball when it's nearly 7 1/2 feet off the ground. A fastball to the bottom of the strike zone travels vertically down nearly 6 feet!
  • Joey Matschulat at Baseball Time in Arlington took a look at McCarthy's PITCHf/x data as well - Profiling Brandon McCarthy: A Pitch F/X Snapshot.