Mark Prior and pitching mechanics

[dawgfan]

OK, upfront I'll admit I'm not an expert in pitching mechanics. With that said, I thought it was a majority opinion that "short-arming" the ball, or bringing the hand up near the ear in the setup portion of the pitching motion was thought to be not as ideal as having the hand stay back and the arm more elongated in this part of the delivery (i.e. after breaking the hands apart at the start of the motion as you start to stride forward).

I've frequently seen Mark Prior described as having "textbook" mechanics, but multiple photos I've seen of his delivery as well as video seems to indicate that he's got somewhat of a "short-arm" delivery (see picture below):

http://espn.go.com/media/mlb/2006/0321/photo/g_prior_134.jpg

Am I way off base on my memory of whether this is considered good mechanics? I have to presume I am given the frequency I've seen Prior described as having such great mechanics, but for some reason I feel like I've read that this style isn't ideal. I'll have to go through my pitching instruction books and see if I can find anything that supports or contradicts my memory here...

[dawgfan]

Dola - this is obviously prompted by the fact that Prior has had consistent elbow and shoulder issues thus far in his career. Maybe it's a coincidence, but maybe not...

[dawgfan]

OK, I'm not dreaming - I checked out my pitching instruction books and one of them specifically mentions short-arming/not getting good extension on your arm in the beginning of the delivery as not proper technique. From a bio-mechanical standpoint, this seems logical to me - short-arming the ball in your delivery is bound to lead to more torque placed on the elbow and/or shoulder as the hand gets whipped around more in the point of bringing the ball toward the plate than having longer extension in your arm would.