Scouting Shawn Tolleson, Baylor University

In his second year back from Tommy John surgery, Shawn Tolleson is expected to be among the top draft-eligible sophomores taken in the 2009 MLB First-Year Player Draft. Baseball America even pegged him as the #29 overall draft-eligible college prospect.

After hitting a groove out of the bullpen last season, Tolleson has returned to the starting rotation for 2009. Through 2 starts, though, Tolleson has yet to find his rhythm. I was on-hand at the Houston College Classic when Tolleson and Baylor squared off against the University of Houston.

Game: February 27, 2009 vs. University of Houston

Pitcher IP H R ER BB K
Tolleson, Shawn 6.2 6 2 2 3 5

Fastball. Tolleson's fastball started out in the upper 80s and might have scraped 90 on a few radar guns but dipped into the mid 80s before he was pulled. The pitch didn't appear to have much sink, but his 10 ground outs and 2 fly outs suggest it was there. His command of the pitch was no better than college-average.

Slider. His slider was all over the place but had good movement when he was able to keep it down. Its break was unpredictable as well, sometimes sharp, sometimes lazy, and sometimes just spinning.

Change up. Despite his limited fastball velocity, Tolleson was able to get decent separation with his change up but without much tumble or fade. The change up was rarely thrown, and right now, it's clearly his third pitch.

Mechanics. Take a look at the video below. A couple of things jump out right away. The most obvious for me is his inverted W.

In Tolleson's delivery, his inverted W leads to a really late forearm turnover and significant reverse forearm bounce. These arm actions put the ulnar collateral ligament at great risk. I am not surprised that he needed Tommy John surgery coming out of high school, and I believe that these mechanics are likely to lead to more elbow trouble down the road.

In the video, it is also quite clear that Tolleson strides toward the third base side. This establishes a drive line that is not directed at the target and requires the trunk and throwing shoulder to compensate by throwing across his body just to get the ball heading toward the catcher instead of the on-deck circle.

This compensation also leads to a violent follow-through where his humerus nearly collides with his face before flying down across his torso.

When his humerus nearly slams into his face, it is likely compressing the long head of the biceps brachii against the bony structures of the shoulder girdle. During deceleration, the biceps flexes and creates tension in its long head which attaches to the glenoid labrum. The tension is magnified by the compression, and when this tension is violent enough, it pulls on the labrum and can lead to fraying and tearing (SLAP lesions). This is not necessarily a problem in Tolleson's case; the 210 frames-per-second video doesn't slow down this part of his delivery well enough to draw a conclusion.

When Tolleson drives his arm across his body, his humerus is next to his right ear one moment and down across his torso the next. This is like whiplash for the supraspinatus muscle, the most frequently torn rotator cuff muscle in overhead-throwing athletes.

Overall. Tolleson is likely still trying to get all the way back from Tommy John surgery, but in this game, he looked less like an early round pick and more like a guy who could go undrafted. Based on his late season success last year, I think it's unlikely that he will continue to struggle, but if his struggles do continue, he could return to Baylor for his junior season.

He has several risk factors for future injury: inverted W, late forearm turnover, reverse forearm bounce, and throwing across his body. As a pitcher who has a significant injury in his past, his mechanics are definitely a concern going forward.

For me, Shawn Tolleson is a wait-and-see player. He has shown great potential in the past, and despite his struggles on this night, he was able to put together a quality start. If his stuff can return to its previous level, he could be worth taking a chance on.