In the beginning of May, Andy Sonnanstine’s record was 4-1 and we noticed that his emergence this season may have been due at least in part to a change in his mechanics. Specifically, Sonnanstine was no longer using different arm angles, one of his trademarks.
Here is the plot we showed you earlier comparing Sonnastine’s release point in ’07 (left) to his release point in his first six starts of ’08 (right).
Since we ran that post Sonny has struggled at times. We decided to go back and look again at Sonny’s Pitchf/x data. The results were surprising.
Here we have added the updated 2008 release point data to the right of the previous two clusters (2008a represents Sonnanstine’s first 6 starts of ’08; 2008b represents all of Sonnanstine’s ’08 starts).
A couple of points stand out…
- Sonnanstine is once again changing arm angles on his pitches, specifically his fastball and his splitter.
- The varying arm angles differ in ’08 as compared to ’07. The different release points appear to be spread more horizontally and he is not dropping his arm as he was in ’07.
Now let’s see how these changes have translated to The Duke’s stat lines…
Once again, a couple of points stand out…
- Sonnanstine’s stat lines are very similar when he is changing arm angles.
- Sonnanstine clearly strikes out more batters when he changes arm angles, but he also gives up considerably more hits and his ERA is higher.
- His walk rate appears consistent whether he is changing arm angles or not.
- Sonny works deeper into games when he is not changing arm angles.
We must point out that we only have a small sample size of starts without changing arm angles (6 starts). Also, we don’t have a game-by-game breakdown, so we cannot be certain when Sonnanstine started varying his release point again, but we do know that it was after his first 6 starts of ’08.
Still, there appears to be a very clear trend: Andy Sonnanstine strikes out more batters when he changes arm angles, but he is a better overall pitcher when he does not.
Sonnanstine No Longer Changing Arm Angles [Rays Index]