Something's wrong with this guy's arm... <img src="http://us.news1.yimg.com/us.yimg.com/p/rids/20020808/i/1028768932.3087065164.jpg">
WOAH!!!! Damn man...that looks sick. He will have no arm in a couple of years...candidate for Tommy John surgery coming up!!!
That's a classic, 12-to-6 curveball where you lead with your elbow and come straight down with your arm movement. Nothing looks wrong with it to me. Pitchers arms are intended to be very flexible and need to be that way in order for them to get a good "snap" on their arm motion, thus providing velocity. That's why most pitching coaches preach the evils of weight lifting for your upper body. There are a few exceptions like Kevin Brown and Kyle Farnsworth, but they are rare.
Trader_Jorge's got it right - that's the arm motion for a typical curveball, just caught in slow motion. Oh yeah, and Freddy Garcia's very good.
I'll tell you what freaks me out is when they show a slow motion shot of Andy Pettite's delivery. He has this tendon or something that jumps out of the side of his elbow. It's sick.
D'oh! When I saw this thread again, I figured I screwed up the M's player - I agree, though, Pineiro is darn good himself. Looks a lot like Garcia, though.