Taking A Look At Joba Chamberlain's Velocity

Throughout the debate on whether or not Joba Chamberlain should be starting or relieving, one thing that keeps coming up is this idea that his velocity suffers in his starts which supposedly means he should be coming out of the bullpen.

While watching games, I have noticed this to some extent, but I am the type of person who doesn’t trust his own eyes. I like to have data to backup my observations, otherwise I end up doubting myself. To remove some of the doubt I have this morning, I went through Pitch FX and pulled out some of the velocity numbers of Joba’s appearances last season and I put together a couple helpful charts.

Here are the numbers during Joba’s 2009 starts:

Date–Opp.	Top Speed	Fastball Avg.
Apr. 12–Royals	95.9 MPH	92.49 MPH
Apr. 17–Indians	95.4 MPH	91.50 MPH
Apr. 24–Red Sox	94.6 MPH	92.39 MPH
Apr. 29–Tigers	96.3 MPH	92.76 MPH
May 5–Red Sox	95.8 MPH	92.26 MPH
May 10–Orioles	97.1 MPH	93.40 MPH
May 16–Twins	97.1 MPH	93.43 MPH
May 21–Orioles	94.5 MPH	91.97 MPH
May 26–Rangers	93.3 MPH	90.36 MPH
June 1–Indians	97.6 MPH	93.91 MPH
June 7–Rays	95.4 MPH	92.03 MPH
June 12–Mets	94.8 MPH	91.87 MPH
June 18–Nats	95.6 MPH	92.17 MPH
June 24–Braves	95.6 MPH	92.33 MPH
June 29–Rays	95.3 MPH	92.02 MPH
July 5–Blue Jays	95.8 MPH	92.40 MPH
July 10–Angels	96.9 MPH	93.57 MPH
July 19–Tigers	96.9 MPH	92.93 MPH
July 24–A’s	96.2 MPH	92.61 MPH
July 29–Rays	95.3 MPH	92.20 MPH
Reaches 110.2 innings,	Previous career high	118.2 in 2005, 112.1 in 2007
Aug. 6–Red Sox	96.2 MPH	92.72 MPH
Aug. 11–Blue Jays	96.0 MPH	92.31 MPH
Aug. 16–Mariners	96.9 MPH	93.02 MPH
Aug. 25–Rangers	96.3 MPH	92.70 MPH
Aug. 30–White Sox	94.4 MPH	91.73 MPH
Sept. 4–Blue Jays	95.2 MPH	92.68 MPH
Sept. 9–Rays	95.1 MPH	92.86 MPH
Sept. 14–Angels	95.0 MPH	92.16 MPH
Sept. 20–Mariners	95.6 MPH	93.02 MPH
Sept. 25–Red Sox	95.4 MPH	92.93 MPH
Sept. 30–Royals	94.8 MPH	91.77 MPH
Avg pre-Aug	95.77	92.43
Avg post-Aug	95.55	92.53
Avg tot	95.69	92.47

I split it up after July because that was the point of the season where his numbers took a nose dive. From the beginning of the season until July 29 he pitched 20 games, all starts, 110.2 innings, a 3.58 ERA, 97 strikeouts and 50 walks. After that he pitched in 11 games, 45.2 innings, a 7.69 ERA, 35 strikeouts, and 26 walks, not counting one relief appearance.

His velocity pre and post July 29 drops, but only slightly. This means that the velocity he had out there was not the main factor for the drop in his numbers. Instead, it is probably a loss in command as his walk total went up slightly compared to his innings pitched.

Let’s now compare these numbers to his numbers coming out of the bullpen:

Date–Opp.	Top Speed	Fastball Avg.
Oct. 4–Rays	95.7 MPH	94.22 MPH
Oct. 7–Twins	94.8 MPH	94.80 MPH
Oct. 9–Twins	96.9 MPH	95.66 MPH
Oct. 11–Twins	96.2 MPH	95.11 MPH
Oct. 17–Angels	95.9 MPH	94.85 MPH
Oct. 19–Angels	96.7 MPH	96.18 MPH
Oct. 22–Angels	98.6 MPH	95.84 MPH
Oct. 25–Angels	96.2 MPH	94.96 MPH
Oct. 31–Phillies	96.2 MPH	94.73 MPH
Nov. 1–Phillies	97.1 MPH	96.00 MPH
Nov. 4–Phillies	96.8 MPH	94.77 MPH
Avg per game	96.46	95.19

Here is where we see the first real difference. In his starts, Joba averages 92.47 MPH with the ability to ramp it up to about 95.69 MPH at times. In his bullpen appearances, his average jumps to 95.19 MPH hitting up to 96.46. So, not only was his average velocity higher in 2009 when he was relieving vs. starting, but he was able to consistently reach higher one-time speeds.

So where does this difference in speed come from? Well the obvious answer is the difference in stamina. Notice the average difference in his fastest pitch during his appearance is only one MPH, but the average overall difference is slightly more than 2.5 MPH difference.

Conclusion: What this shows me is that it’s not all about velocity when it comes to Joba’s success on the mound. Yes, he absolutely has a higher average velocity out of the pen by about 2.5 miles per hour, but I think the numbers pre and post July 29th tell me more than the difference than between starting vs. relieving numbers. Like I said before, there was hardly a difference in his velocity after he reached 110 innings, but the stark difference in the numbers means that it is probably more about command and pitchability for him than velocity.

It took a little while to pull all of these numbers and I’m hardly a statistician, so there is probably something I’m overlooking here. I just wanted to pull the numbers and see if anything jumped out at me. I also wanted to try to get an idea of what the actual difference in his velocity was and not just the perceived difference. Hopefully I can have some other people look at these numbers and point out anything important that I might have overlooked.

Date–Opp.	Top Speed	Fastball Avg.
Apr. 12–Royals	95.9 MPH	92.49 MPH
Apr. 17–Indians	95.4 MPH	91.50 MPH
Apr. 24–Red Sox	94.6 MPH	92.39 MPH
Apr. 29–Tigers	96.3 MPH	92.76 MPH
May 5–Red Sox	95.8 MPH	92.26 MPH
May 10–Orioles	97.1 MPH	93.40 MPH
May 16–Twins	97.1 MPH	93.43 MPH
May 21–Orioles	94.5 MPH	91.97 MPH
May 26–Rangers	93.3 MPH	90.36 MPH
June 1–Indians	97.6 MPH	93.91 MPH
June 7–Rays	95.4 MPH	92.03 MPH
June 12–Mets	94.8 MPH	91.87 MPH
June 18–Nats	95.6 MPH	92.17 MPH
June 24–Braves	95.6 MPH	92.33 MPH
June 29–Rays	95.3 MPH	92.02 MPH
July 5–Blue Jays	95.8 MPH	92.40 MPH
July 10–Angels	96.9 MPH	93.57 MPH
July 19–Tigers	96.9 MPH	92.93 MPH
July 24–A’s	96.2 MPH	92.61 MPH
July 29–Rays	95.3 MPH	92.20 MPH
Reaches 110.2 innings,	Previous career high	118.2 in 2005, 112.1 in 2007
Aug. 6–Red Sox	96.2 MPH	92.72 MPH
Aug. 11–Blue Jays	96.0 MPH	92.31 MPH
Aug. 16–Mariners	96.9 MPH	93.02 MPH
Aug. 25–Rangers	96.3 MPH	92.70 MPH
Aug. 30–White Sox	94.4 MPH	91.73 MPH
Sept. 4–Blue Jays	95.2 MPH	92.68 MPH
Sept. 9–Rays	95.1 MPH	92.86 MPH
Sept. 14–Angels	95.0 MPH	92.16 MPH
Sept. 20–Mariners	95.6 MPH	93.02 MPH
Sept. 25–Red Sox	95.4 MPH	92.93 MPH
Sept. 30–Royals	94.8 MPH	91.77 MPH
Avg pre-Aug	95.77	92.43
Avg post-Aug	95.55	92.53
Avg tot	95.69	92.47

 

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