Sunday, January 11, 2015

Strasburg's Release Point

In pulling together some of my research for the Stephen Strasburg review, I was browsing over at Brooks Baseball where they have some great features, including the ability to review release points via the Pitchf/x tool. Check out the 2014 season of release points for Strasburg here. Starting on his 7/29/2014 start versus the Marlins, Strasburg shifted to his right by half a foot. To see this in video evidence, here is Strasburg from a start against the Phillies in early July. Pause at any point in his wind up (the first pops up at 5 seconds), and see where his back foot is planted and how that drives his release point. Compare that to this video of a start against the Braves in September (pause around 8 seconds) and notice that he is now at the right extreme of the rubber.

I think this is really cool, and something you might not pick up on without the awesome Pitchf/x tool. Why would Strasburg make this shift? Well, shifting left or right on the rubber obviously changes your release point and the how the batter sees the ball. Generally, as a right handed pitcher, shifting to the right of the rubber should make it tougher for the right handed batters to see the ball, but potentially easier for left handed hitters. Interestingly, if you change the date filter on that Brooks Baseball page to his career, this isn’t something Strasburg has done before in his career. Clearly, something precipitated the change halfway through the 2014 season.

What do the stats say? Post-change, Strasburg put up a 2.20 ERA, a 3.15 FIP, and a 2.69 xFIP in 77.2 innings versus 3.67 ERA, 2.83 FIP, and 2.49 xFIP pre-change in 137.1 innings. Keep in mind, we are looking at a bit of a small sample size problem here, but there is not much difference in the overall results. Yes, the ERA after the change is higher, but the xFIP is almost identical pre-change and post-change. Strasburg got a few more swings and misses before the change, a 12% swinging strike rate versus a 9.8% rate, but that seems like noise to me. 

How did Strasburg fare versus right handed hitters and left handed hitters after the change? Against right handed hitters, Strasburg’s change up generated more whiffs (35.7% post-change compared to 26.6% prior). Against left handed hitters, his curveball was actually more effective post change, with whiffs 12.2% of the time compared to 9.5% before the change. His fastball did seem to get hit a little harder against lefties after the change, with a 7.9% FB rate and 1.9% HR rate compared to 4.18% FB and 0.6% HR rate beforehand. 

While the peripherals show some differences, as you would expect, the results don’t show much of a change over the small sample size. For me, the two biggest questions this raises are: 1. What caused Strasburg to make this change? 2. Will Strasburg continue this change in 2015? Unfortunately, I don’t have the answer to either of these questions, but it will be interesting to watch where Strasburg lines up in 2015. That might tell us all we need to know.

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