A Baseball Weblog

Wednesday, June 9, 2010

Strasburg through PITCHf/x

I'm not going to say a whole lot about Stephen Strasburg's MLB debut yesterday --- we all know that 14 strikeouts and no walks over 7 innings is other worldly for a first game. And surely that's been said many times this morning already. I would, however, like to put on my PITCHf/x glasses and dive into Strasburg's outing from the dimension.

The report on Strasburg was that he throws HARD. That's just what he did yesterday, averaging 97.95 mph on the 50 4-seam fastballs he threw. The 8 sinkers he threw averaged 96.4 mph. Here is how he distributed the velocity on his 4-seamers yesterday:

So, he was sitting 98-99 yesterday. That's pretty impressive.

But it's not all about the velocity with Strasburg. He is able to support the upper 90s cheese with two offspeed offerings: a curveball, which averaged around 82 mph yesterday, and a hard changeup, which averaged around 90 mph. Both of these pitches were dynamite for him yesterday, with the exception of the one changeup he hung for a home run to Delwyn Young. This is data from only one game, so it's unclear as to whether the pfx_z values are fully reliable, but Strasburg's changeup appeared to be generating a ridiculous amount of vertical break yesterday; its vertical spin deflection averaged only 0.22 inches above a theoretical spinless pitch, which is good for a slider, let alone a changeup. From what I saw, it looked more like a splitter than a typical changeup.

For the whole game, Mr. Strasburg got 18 swings-and-misses. Over 41 total swings, that makes for ridiculous .439 whiff rate. The breakdown for his three pitches (the sinker was swung at twice and was the only offering to not be whiffed at):

Pitch#Swing#Whiff Rate

And how about those 14 strikeouts? Of them, only two were looking --- one on a fastball, one on a curveball. This is what his 14 strikeouts look like in pie form:

Remember, of course, all of this comes with severe small sample size warning. And this was the Pirates he was facing. But that doesn't mean we can't get excited, right?

Gameday PITCHf/x data is from MLB Advanced Media; it can be easily accessed via this tool.

DISCLAIMER: The distinctions between Strasburg's two fastballs aren't that easy to distinguish, so these classifications are subject to change.

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