As requested, by readers Mark and Heater, I’ve done some analysis of Joba Chamberlain. Most people are familiar with his body of work statistically, so I’ll skip that for this analysis and focus only on the mechanical side of the top prospect in pinstripes.

Source: pitchingclips.com

Unfortunately for Yankees fans, I don’t really like what I see…

Tempo/Arm Action

His tempo is pretty good. Depending on when you define maximal leg lift, Joba’s anywhere from 18-20 frames into footplant. We’ll say it’s 19 frames - that’s fast, even if it doesn’t really look that quick.

However, Joba’s arm action is not good at all. There are two major things wrong with it:

1) He has signs of the “Inverted L” and/or “Inverted W”

The “Inverted L” is a term invented by Chris O’Leary. It refers to the position of the pitching arm right before footstrike, and can be a sign of problems to come. The “Inverted W” is when a pitcher brings his elbows above the level of his shoulders in a position of hyperabduction. This can cause impingement problems down the line and also leads to rushing. Here’s a few stills of what I mean:

Possible Inverted W

Possible Inverted L

These particular positions are often found in pitchers who have an “elbowy” or “short” arm action, and it’s often promoted as a good thing. Who remembers Mark Prior’s “flawless” mechanics? Take a look at this:

Mark Prior’s Inverted W

We all know Prior’s injury history, now don’t we?

Here’s an example of a severe Inverted L (or as I also call it, “Hung Arm Syndrome”):

B.J. Ryan’s Inverted L (credit: Chris O’Leary)

2) His arm is late at footstrike

Problem #1 leads to problem #2 very frequently. In this case, his arm has not passed through the horizontal plane axis of his shoulders at footstrike. This will cause unnecessary force in the external rotation phase of the pitching motion and is evident when you see how far Joba’s arm lays back in that phase:

Ball Release / Followthrough

It is clearly evident that Joba has a lightning-fast arm. Check it out:

Unfortunately, that doesn’t mean he has a good followthrough phase; he doesn’t.

Compare him to a pitcher I like, such as Zack Greinke:

Joba doesn’t really do anything I like in the followthrough phase except for slapping his shoulder with his glove, which, to his credit, is quite rare in the MLB. He does a decent job of pointing the PAS shoulder at the target, but he has an abrupt followthrough and doesn’t bring his PAS leg up and around his body to give his decelerator muscles a break.

Conclusion

I think Joba’s injury concerns are well-founded. He has a lot of the classic signs of hyperabduction, rushing, hung arms syndrome, and a bad followthrough. That he does a few things right and is blessed with obvious genetic gifts does not make him a good bet to avoid serious injury in the future. Throw in some conditioning concerns and you have a legitimate reason to fear for Joba’s future.