Just 23 years old, Marcus Stroman carried the burden of high expectations on his diminutive shoulders heading into Spring Training this season.
In 130.2 major-league innings in his 2014 rookie campaign, the 2012 first round pick out of Duke lived up to the expectations of a fast riser, posting a respectable 3.65 ERA that looked good on the surface but became more impressive when looking at his peripherals and seeing that he outperformed his ERA to the tune of a 2.84 FIP, 3.17 xFIP, and 3.18 SIERA, all of which owed largely to a 3.96 K/BB. His command was sterling, walking just 5.2% of the hitters he faced or 1.93 BB/9.
While his 5'8"/5'9" frame pushed many prospect evaluators to assume his lack of height would force his transition to the bullpen for the standard "small guys can't handle the workload of a starting pitcher" reasons, Stroman's stuff was never a point of concern. When combining his command with his starter's repertoire, it was easy to see why a strong 2014 emboldened many to predict a breakout season from the former Blue Devil.
Then the right-hander tore the ACL in his left knee in Spring Training, at that point believed to be a season-ending injury.
Fortunately for the Blue Jays (and unfortunately for the Royals today), Marcus Stroman's recovery was swift, and his road to recovery consisted of just two minor league starts totaling just 7.2 IP before jumping back into the fray at the major-league level.
Stroman notched 27.0 innings in his four regular season starts. With his four starts occurring against AL East foes in hitter-friendly parks, Stroman allowed a 1.67 ERA, 3.54 FIP, 3.34 xFIP, 3.28 SIERA. His velocity has been down roughly 1.5 MPH from pre-injury marks, though the reasons for this are not related solely to building back strength (more to come on that).
While he didn't pitch enough in 2015 for it to have meant much, analytically speaking, combining his numbers from his two major-league stints shows a 3.5 fWAR/3.2 rWAR pitcher with a 3.31 ERA, 2.96 FIP, 3.20 xFIP, and 3.21 SIERA over 157.2 IP, sporting a 7.36 K/9 and 1.96 BB/9 in that time.
In looking at how he pitches, tendencies become very clear when looking at his heat maps:
Tendencies don't get much clearer than that. As one could easily surmise from these heat maps, Stroman lives low.
Looking at his pitch selection, a few interesting things pop out:
Midway through 2014, Stroman basically scrapped his four-seamer and moved almost entirely to the sinker. The velocity drop mentioned earlier is actually less drastic when looking at his fastballs when broken up by PITCHf/x types, where he throws his slower two-seamer 41.0% of the time now versus just 13.1% of the time last year, though they get lumped in together when looking at non-PITCHf/x pitch data. His velocity in the regular season was still lower on these pitches, but the difference on average was 0.7 MPH on the four-seamer, 0.9 MPH on the two-seamer (sinker), and 0.7 MPH on the cutter, marks considerably less alarming than the overall 1.5 MPH drop on his fastballs.
The other noteworthy development is the increased usage of his slider. While he went to the slider just 7.8% of the time in 2014, he is throwing it roughly twice as often in 2015, 16.9% of the time. Having changed his arm slot to a more over-the-top delivery--as detailed by Eno Sarris at FanGraphs--the slider now has more vertical break than his curveball, a peculiar bit of information that makes him basically the only pitcher who can make this claim.
Despite its change in movement and its increased implementation, the slider has not actually become a more effective pitch, producing -0.8 wSL runs compared to a positive value of 0.9 last year.
His curve, however, has taken on more horizontal run corresponding to arm-slot change. With the change in movement on the curveball, it went from -3.0 to 1.8 wCU runs. A small-sample size alert should be taken into consideration with these usages and values, but his overall shift in tendencies can probably be expected to continue today.
Tonight, look for Stroman to build everything off of his sinker, going to his breaking balls as his primary secondary offerings while mixing in his cutter and change for different looks roughly half as often as the breaking balls. In his two starts in the ALDS, Stroman barely used his four-seamer, but he does have a sixth pitch he can mix in for a different look, though this will probably only happen a few times.
Royals right-handed and left-handed hitters will struggle equally with Stroman, as his wOBA split is .276 for LHH and .278 for RHH. Lefties hit .040 lower but enjoy a .113 ISO compared to a .064 ISO from righties.
The first couple of times through the order could be rough for the Royals. It would stand to reason that they would be best served trying to work the count and see as many of his pitches as possible, as his repertoire is varied and limits the damage done to him quite adeptly.