What’s up with Jeff Karstens’ shoulder?

We won’t know for sure what’s wrong with Jeff Karstens’ shoulder until he gets it looked at later this week, but that doesn’t have to stop us from trying to see if his problem was apparent from his performance. Karstens got hit HARD in his one inning of work last night and when I saw D-Back beat writer Nick Piecoro’s tweet about his 84 mph fastball, I figured it was worth looking in to. As it turns out, Karstens pretty clearly didn’t have his best zip on the ball last night. This is a plot of all of Karstens’ fastballs and sinkers from his three 2012 starts. 

Jeff Karstens Fastball Velocity
It’s maybe also worth noting that he lost some velocity from his first start to his second start, but that’s pretty much all hearsay until we know how bad his shoulder inflammation is. 

The other thing worth noting is that nine of Karstens’ 20 pitches tonight were off-speed (curve, slider, change). In his first start, only 37 of his 85 pitches were off-speed pitches. In his second start, it was only 28 of 71. I wasn’t paying close enough attention in the first to see if Karstens was shaking off a lot of signs and 20 pitches is hardly a big enough sample size to draw a pitch selection conclusion from, but even if the reason for Karstens’ departure wasn’t IMMEDIATELY apparent in the middle of the game, it’s probably a safe guess that he didn’t feel at all comfortable with his fastball last night and that’s what got him pulled so quickly.

Hopefully this won’t be that big of a deal, but a drop in velocity described as “shoulder inflammation” is always going to make me nervous, even though this is a small change that’s only really manifested itself once (twice at most). 

Pat Lackey

About Pat Lackey

In 2005, I started a WHYGAVS instead of working on organic chemistry homework. Many years later, I've written about baseball and the Pirates for a number of sites all across the internet, but WHYGAVS is still my home. I still haven't finished that O-Chem homework, though.