Wilfredo Boscan. Last season, as an 18-year-old Venezuelan pitching in the United States for the first time, Wilfredo Boscan was among the youngest pitchers in the Northwest League, regularly facing players 2-4 years his superior.
Not only was he one of the youngest pitchers in the league, he was also one of the best pitchers. Boscan went 9-1 and averaged just over one strikeout per inning while maintaining a 6.36 K/BB ratio. On top of that, Boscan has been lauded by several people for his ground ball rate in each of the past two seasons.
Boscan took the mound on March 19, 2009 in a Low A spring training game on the back fields at the Rangers complex. The following video was shot at 210 frames per second.
Boscan has very smooth mechanics, but he has a few inefficiencies and a pretty noticeable reverse forearm bounce. Boscan starts his delivery with his shoulders lined up outside the right-handed batters box, and he brings the ball behind his back before striding closed. Instead of using his hips to drive around his closed front leg, he drives his pitching shoulder over the top of his front leg. This is good when it eliminates forearm flyout, but in Boscan's case, it does not.
Boscan appears to pronate on his fastball, but it is hard to tell for sure at 210 fps. He does, however, clearly supinate when he throws his breaking ball. In combination with his forearm flyout, this action will eventually lead to discomfort (or worse) near the olceranon process of his ulna.
His follow through is pretty clean compared to most pitchers, but because he uses his pectoralis major to horizontally flex his humerus as most pitchers do, I have some minor concerns about future rotator cuff problems.
Despite the number of flaws discussed above, Boscan's mechanics are pretty typical for today's pitchers. Based on his mechanics alone, I would not say that Boscan is at any greater or lesser risk for arm injury than an average professional pitcher.
Ryan Tatusko. Drafted in the 18th round of the ballyhooed 2007 Texas Rangers draft class, Ryan Tatusko spent all of last season pitching for Low A Clinton. Tatusko features a low-90s fastball that might cut, sink, tail, or even be a little too straight. He calls his breaking pitch a slurve, but when I saw it, it looked like a good, hard curve ball.
On March 20, 2009, Tatusko toed the rubber in a AA spring training game. In the bullpen, his fastball was blazing and his slurve had a gigantic break. I was really impressed.
It was a bit of a different story once he climbed up onto the hill. The fastball looked like it was down a couple of ticks, and the slurve was inconsistent. If you've ever been a pitcher, you've probably had one of the opposite bullpen days.
The following clip was filmed at 210 frames per second, showing several pitches from the windup as well as the stretch.
Tatusko is a serious drop-and-drive guy. He gathers himself at the top and then sits down on his back leg before driving forward. The angle is rough, but it looks like he only lands slightly closed (which is better than more closed). After his drive, he pulls forward off the rubber to help keep his center of mass moving forward. This is excellent.
Tatusko also has a very good ball pick-up. It isn't quite the pendulum swing that I like to see, but he doesn't rely on powerful external rotation and the ball passes shoulder height before the elbow. This helps reduce the inertia of reverse forearm bounce, though, in Tatusko's case, it still has a presence.
He has some minor reverse shoulder rotation, but he has a nearly straight-line shoulder drive. Tatusko tilts his shoulders toward the glove side and really picks up his pitching elbow. By picking up his elbow, he limits the downward motion of reverse forearm bounce. As I said above, there is still a noticeable bounce, but Tatusko does a very good job of reducing it.
Tatusko's shoulder tilt also helps get his arm into a more vertical position which limits forearm flyout and allows for a greater kinetic contribution from the triceps brachii - another mechanical plus.
After Tatusko's primary arm deceleration, the momentum of his forearm pulls his humerus into his chest. The forces involved here are far less significant than during primary deceleration, so I think it looks worse than it really is.
To put all of this in perspective, Tatusko's promising mechanics do not guarantee that he will not suffer an injury. He has fewer risk factors, but nothing is written in stone. Overall, I really like how he throws the baseball.