A Breakdown of Stephen Strasburg

Stephen Strasburg is a big deal.  He was from the point of his debut in 2010 and he still is today with the trade deadline looming.  No, he will not be getting traded, but his most recent injury may prompt the Nats into going after reinforcements such as Sonny Gray.  Strasburg left his most recent start before he could get through 3 innings with forearm stiffness.  This is not what the Nationals wanted to hear in the midst of a hopeful World Series run.  The point is that Strasburg is an elite pitcher and there is no way to replace him.  We will break down what makes Strasburg so elite and valuable.

Lets start by talking about Strasburg’s curveball.  He uses it 23% of his pitches and is his primary off speed pitch.  According to Fangraphs pitch value, it is his best pitch.  He is using the pitch more this year than he was previously.  Last year he was tinkering around with a slider.  Here are his ranks for some of the measurable categories of his curveball:

BA xwoba launch speed spin rate velocity release extension whiff %
10 19 10 10 5 4 16

These rankings are out of 61 pitchers who throw their curveball over 10% of the time.  We can see that Strasburg is in the top 10 in many of the categories.  Here is a look at his radial chart from Baseball Savant:

 Hitters only have 2 balls greater than solid contact all year.  Most of his balls are topped.  Here is Strasburg striking out Daniel Descalso:


If you notice in the video, he does not have overpowering movement on his pitch.  He has the 9th highest horizontal movement on his curveball but its very subtle.


What many believe to by Strasburg’s best pitch is is changeup.  This year he is using his changeup more than ever before due to his great success with it.  The velocity on his changeup is on average about 7 mph less than his fastball.  Here are some plots to illustrate how elite his changeup is this year with Strasburg being the red dot:

The graph on the left shows that despite an average spin rate on his changeup, he is elite in his ability to miss bats.  On the right, the graph shows how elite he is in missing bats and how it transfers to having the the best woba among pitchers who throw changeups.  Here is a look at his changeup:


Part of what makes his changeup so effective this year is his ability to locate it and getting hitters to swing outside the strikezone.  Here is his pitch heatmap:
He consistently locates his changeup out of the zone.  And because he is consistent in his release point from his fastball and changeup he add great deception.  Similar to his curveball he has the ability to have above average horizontal movement on his changeup.

All put together Strasburg is having a fantastic season.  He is making batters chase out of the strike zone more than ever this year and missing bats.  We have always known he can throw gas and strike batters out with his fastball, but this year more than ever he is mixing his pitches more and looking to off speed pitches to get swing and misses.  He is using his fastball less this year than ever before.  Strasburg is reportedly making his next start, but the Nats will be cautious.  Strasburg is arguably the best number two starter in the league and is needed for a deep playoff run.

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