Pitching Profile: Toronto Blue Jays Starter Marcus Stroman

Last year the Toronto Blue Jays won the AL East for the first time in 21 years. This year, they return the same the lineup that powered them down the stretch. David Price bolted for Boston and a bigger paycheck, but he is being “replaced” by a young potential ace who is now fully recovered from a torn ACL. Ian York profiles Toronto Blue Jays starter Marcus Stroman to find out what sets him apart from the rest of the rotation, and if he can possibly fill Price’s shoes.

In 2015, the Toronto Blue Jays led all of baseball in offense, but were only slightly above average in pitching. That may not change much in 2016: former ace R.A. Dickey seems to have settled into consistent averageness, Marco Estrada is more likely to be league average than the above-average pitcher he was in 2015, and Aaron Sanchez is still unproven. J.A. Happ had a very good second half to his 2015 that correlated with a change in his pitch usage, and it would be great if he can maintain that, but again, he has a long history of mediocrity; very few pitchers abruptly become aces at the age of 32.

On the other hand, it is not unprecedented for pitchers to become aces in their second year in the majors, which is what right-hander Marcus Stroman apparently did in 2015, albeit in just seven appearances (counting post-season games). Stroman is just 24 years old, and has dramatically changed his repertoire along with his increased success, both of which suggest that he may have found a way toward sustainable excellence.

Stroman throws six pitches: four-seam fastball, two-seam fastball (or sinker), cutter, slider, change, and curve. The cutter and change were thrown almost entirely to left-handed batters (71 of 73 cutters, and 71 of 75 changes). His slider and curve are both solid major-league pitches, but Stroman’s breakout in 2015 correlated with the his sinker use. Here is Stroman’s pitch usage in the past two years (2015 includes his three post-season games as well as his four regular-season games, to get as much data as possible from his short season):

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Midway through 2014, Stroman began to replace his four-seam fastball (“FF”) with the sinker (called “FT” here), and in 2015 he barely threw any four-seams, going from 35.9% four-seam use in 2014 to 5% in 2015, according to Brooks Baseball:

For most pitchers, sinkers and four-seam fastballs are very similar pitches. Four-seam fastballs are thrown with maximum backspin, causing them to rise relative to the path they would follow relative to gravity. In theory, sinkers (two-seam fastballs) are thrown with the spin axis tipped more sideways. With less backspin, the pitch rises less and sinks relative to the four-seam path (although it still rises slightly relative to the path it would follow from gravity alone).

With most pitchers, though, the two- and four-seam versions blend into each other, and the distinction between the pitches is fairly artificial.  Not so with Stroman. His four-seam fastball and sinker are very different pitches. Here are his pitches, shown by horizontal and vertical break length and by speed:

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[Editor’s note: To see how four- and two-seamers normally blend click here for Dallas Keuchel‘s 3D graph. ]

Compare the four-seam cluster (red) with the sinkers (blue). Although their speed is very similar, the four-seams have significant vertical break (that is, they rise 6 to 10 inches above their gravity-only path) and moderate horizontal movement (5 to 7 inches or so). The sinkers are a completely distinct cluster, with very little vertical rise (less than 5 inches) and more horizontal movement (up to 10 inches). Stroman’s two-seam fastball in 2015 averaged just 1.8 inches of vertical break, far better than the league average of 5.65 inches. His sinker’s vertical movement was 11th of the 143 pitchers who threw at least 200 sinkers in 2015. Most of those ahead of him were sidearm pitchers like Justin Masterson and Brad Ziegler, whose natural pitching motion makes it far easier to throw pitches without backspin, or sinkerball specialists like Charlie Morton.

Also compare the sinker with the changeup (“CH”: orange). His changes have almost identical vertical and horizontal movement to the sinkers, but are about 8-mph slower. Although the change on its own was hit hard in 2015, if Stroman can increase his confidence in this pitch it should be an excellent way to disrupt batters’ timing.

Back to the sinker: The separation from the four-seam fastball can be seen even more easily when looking at (inferred) spin direction. (These data are from PITCHf/x, which does not directly measure spin, but infers “useful” spin based on the pitch movement. Pitchers can put a significant amount of spin on baseballs that does not influence pitch movement, and we are ignoring that spin here.)

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Stroman’s 2014 is on the left, and 2015 on the right. In both cases, it is easy to see that the sinker (“FT”) has a different spin direction than the four-seam. A spin direction of 180° is pure backspin; a direction of 270°  is pure sidespin. Stroman achieved excellent separation in spin directions in 2014, but his sinkers in 2015 are even more extreme; a significant number of them are thrown with no backspin at all and some even have slight forward spin (more than 270°), corresponding to the sinkers in the 3D chart that have negative vertical movement.

Stroman is a young pitcher who is still developing his approach. In 2014 and especially in 2015, he added a truly extreme pitch to his arsenal. Unlike most pitchers with a dramatic sinker, he does not rely solely on it, but mixes it in with five other solidly major-league pitches. There is every reason to expect him to continue at the high level he showed in his brief 2015 appearance.


Follow Ian on Twitter @iayork.

All data compiled from PITCHfx and Baseball-Reference.com.

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