A Look at Casey Kelly’s Velocity in 2012


Casey Kelly is widely regarded as one of the Padres top prospects.  He sits close to the top of most people’s prospects rankings for the team and he was recently ranked as the 69th best prospect in baseball by Jonathan Mayo at MLB.com.  However, Kelly’s stock has slipped in the last year as Mayo had him as the 14th best prospect in baseball at the end of the 2011 season.  The most likely reasons for the fall-off are 1) He sat out most of 2012 with a right elbow injury and 2) He was quite ordinary in 6 starts at the end of that season.

At the time of those 6 starts, much was made of his velocity.  Although he often came out strong in the first inning, the velocity on the fastball seemed to dip after that.  This is his velocity chart for his first start on August 27, 2012 against the Atlanta Braves (Courtesy of Brooksbaseball.net).

We see that the velocity of his fastball (and other pitches) does decrease as the pitch count increases.  His average fastball was 91.7 mph and in the first inning he touched 95.4, but by the end of his night, his fastball was below 90.

His next start against the Colorado Rockies was a little better:

While the decrease in velocity is not as pronounced, he wasn’t throwing as hard in the first inning to begin with.  His average FB was 90.8 and his max was 93.4. This trend continues with his next start when his average FB was down to 89.0 and his max FB was just 91.5 (which was the speed of his average FB in the first start).

Just for comparison, I randomly picked a start made by Edinson Volquez in the middle of the season.  This was Volquez’s velocity chart for July 19th against the Houston Astros.

We see that while there is some drop off in velocity at the end, it’s actually in the middle innings that Volquez is throwing the hardest.  Also, Volquez’s drop in velocity comes at a much higher pitch count than Kelly’s drop-offs occur.

What do we take from this?  Maybe (probably?) just that coming off his injured elbow, Kelly didn’t have the endurance to be an effective starting pitcher.  We can take some encouragement from his final start of the 2012 season (Sep. 27 against the Dodgers) as he appeared a bit stronger:

During this start, his average FB was back up to 91.7 and his max was 93.4.  Was he truly stronger by the end of the season or did he just know that this would be his final start so there was no need to leave anything in the tank?

I know I’ll be watching Kelly’s velocity closely as he tries to make the Padres starting rotation this season.

Note: All velocity charts are courtesy of Brooksbaseball.net