In February of this year, reporters noted that Atlanta Braves phenom Tommy Hanson would be altering his mechanics to reduce strain on his shoulder. In June of 2011, Hanson had been shelved on the 15-day disabled list due to shoulder tendinitis—more specifically, inflammation in the posterior (rear) aspect of the rotator cuff.
On the mechanical changes:
“I’m really just cutting out that pause,” Hanson said. “I felt like I was throwing with all arm. Also, by changing, I could kill two birds with one stone as far as cutting down the running game. Somebody gets on and they have just run all day. I think it’s going to help both.”
However, it’s no secret that, Hanson has started to struggle. He was beaten badly by the Mets on July 14, giving up six earned runs in 5.1 innings pitched, his strikeout rate has dropped significantly in the last year, and his fastball velocity has declined for a second straight year. It went from 92.7 mph on average in 2010 to 91.1 mph in 2011 (his injury probably played a big role here) and just 89.8 mph so far in 2012.
Some have wondered if Hanson’s mechanical changes have caused the reduction in fastball velocity and have also questioned whether changing his mechanics will actually help protect his shoulder.
Hanson’s mechanics: a comparison
Here’s a look at Hanson’s mechanics when comparing his 2010 version (93 MPH) to a 2012 version (90 MPH):
I used to be a big fan of Hanson’s mechanics, but upon a closer look, I notice some deceleration issues. When comparing the videos, you can clearly see that in the 2010 version (dark jersey) he has significant arm recoil at the end of the throwing phase. Recoil tends to indicate poor deceleration/follow through and overly stresses the posterior aspect of the shoulder. In the 2012 version, you can see Hanson has significantly less arm recoil (almost none).
Hanson’s arm recoil in 2010 is very clear in this slow-motion clip from the side:
While Hanson said his arm slot hadn’t changed, PITCHf/x seems to disagree. Look at how his release point has morphed between last year and this year (controlling for time period):
(if it doesn’t loop, right-click and open in new window to see the animation)
Hanson seems to use less violent rotation in the lower half in his revamped delivery, which he alluded to when interviewed about the subject. While he’s cut down the “pause,” it’s still noticeable. I think it’s misguided to say that the “pause” in his delivery is responsible for posterior shoulder stress; Hanson’s upper body is simply too linear into follow through, which cuts off the deceleration path his arm can follow. Better shoulder rotation and sticking the pitching arm shoulder into the target will help with this; a great example is Trevor Bauer:
I think it’s pretty clear that Hanson has cut down on some of the things that will stress his posterior shoulder: The recoil has been significantly diminished. However, so is his fastball velocity, and I highly doubt that will return. A better solution to cutting down on unnecessary posterior shoulder stress and retaining the fastball velocity may be learning to use the shoulders in a more complete manner to provide a longer, more efficient deceleration path. The “dart-throwing” aspect of his arm action is far down the list of things to worry about, if it’s even something to focus on at all.
However, this is a perfect example that shows that rotation = velocity. Cutting down on rotation in hopes of solving another problem will come at a price. Can Hanson use these mechanics and diminished fastball velocity to return to form as a 3.20 – 3.80 xFIP kind of pitcher, a clear No. 2 in the rotation? Only time will tell. But while going from 93 to 90 might not be too bad, going from 90 to 88 could be a drastic difference to hitters, as fastball effectiveness does not diminish in a 1:1 ratio with lost velocity.