Marcus Stroman’s Strikeouts

There were big expectations for Marcus Stroman coming into last season on the heels of a strong rookie campaign that saw him throw 130.7 innings of 3.65 ERA, but a very impressive 2.84 FIP. A heavy groundball focus, 4.0 K:BB ratio, and stifling homers (0.5 per 9) laid the foundation for the lofty expectations before a torn ACL in Spring Training put all of that on hold. To his credit, he returned in time to make four starts in the regular season and three more in the postseason which rejuvenated the hype to the point where he was the 26th starter off the board this past draft season.

I don’t need to a deep breakdown of his season to show that it didn’t live up to said hype. His 4.37 ERA says it all. However, he did have a 3.71 FIP and the breakdown of his season might actually be enough to yet again foster some hype heading into his age-26 campaign. He likely won’t go as a top-30 arm again, but those who look beyond the surface stats will see a tale of two halves, the second of which saw a surge in strikeouts unlike anything he’d done before and at no expense to his league-best 60% groundball rate. This jump in strikeouts will be our focus today.

(By the way, I’m splitting the sample right down the middle – April through June, July through September.)

In the first half, he pitched to a 5.33 ERA in 101.3 innings with just a 16% strikeout rate – worse than the passable-but-modest 20% rate he’d posted in 2014-15. His fastball was the biggest issue, netting a 7% strikeout rate that stood 94th of the 96 qualified starters. This folds in both his four-seamer and sinker, but neither were anywhere near the 16% league average strikeout rate for fastballs. Adding in the cutter boosted him to 10%, but he still slotted just 81st. The soft stuff had a passable 31% mark, just over the 29% average, but the slider, curve, and change accounted for just 30% of his plate appearances, muting the impact of those strikeouts.

He flipped the proverbial script in the second half, posting a much better 3.42 ERA with a 23% strikeout rate. If you prefer K9, he added two full strikeouts to his rate boosting it up to 8.3 in the 102.7 innings of work. There was improvement with the four-seamer, but more in the “less-is-more” vein than anything else. It had just a 6% rate in 146 PA in the first half, but then a 30% mark in 47 PA in the second half. He funneled that excess to both the cutter and sinker, with the former really driving the overall surge. He maintained his 24% strikeout rate with the cutter while essentially doubling the plate appearances ended with the pitch.

Cutter & Sinker by Half
CT-1H 58 24% 0.727
CT-2H 114 24% 0.545
SI-1H 103 9% 0.765
SI-2H 188 9% 0.798

Stroman was more judicious with his soft stuff, but netted almost as many raw strikeouts. In the first half, he got 39 strikeouts on 128 PA with the three pitches. In the second half, he got 38 in 71. As is often the case, the heat sets up the off-speed and in Stroman’s case, it was a matter of picking the proper heat to dispense. His 93-94 MPH four-seamer isn’t bad (in fact, it could be a key to righties tonight, but more on that in a minute), but the sinker and cutter are just better. He only sacrifices 1 MPH with the sinker plus the movement while the cutter works more 90-91, running away from righties and boring in on lefties. In fact, it was the latter that spurred him against southpaws.

In that second half, he started burying that cutter in underneath the hands of lefties with much better results yielding a .597 OPS and 22% strikeout rate in 68 PA, compared to a .776 and 19% in 37 PA during the first half. Those added plate appearances all came out of the four-seamer, a pitch lefties brutalized in the first half: 1.047 OPS, 4% K rate in 68 PA; .769, 25% in 24 second half PA. The cutter will be his key pitch tonight against Hyun-Soo Kim, Matt Wieters, Chris Davis, and Michael Bourn.

Working up in the zone isn’t generally Stroman’s strength, especially in the aggregate, but it became a second half weapon for him to use when he was ahead in the count, especially with the heat. Fastballs (counting his four-seamer, sinker, and cutter here) in the upper half of the zone to righties when he was ahead in the count were pelted to the tune of a .974 OPS (and 22% K rate) during the first three months of the season.

We’re parsing here for sure as it was only 18 PA, but it speaks to his struggles in putting away righties which led to a 5.33 ERA. The league had a .504 OPS in that rather specific split (fastballs, up, to righties, when ahead). In the second half, he had a .600 OPS in those situations with a 36% strikeout rate in 25 PA.

He also didn’t allow a single hit off the slider to righties in 16 PA during the second half with 10 strikeouts, aiding a 79-point overall improvement in OPS and six percentage point jump in strikeout rate to 23%. The slider always has been, and will remain a big key to righties tonight. Mark Trumbo had just a .194/.224/.330 line against righty sliders this year with a 27% strikeout rate in 107 PA. Manny Machado was better when he made contact at .280/.284/.467, but actually had a worse strikeout rate at 30%. Adam Jones went .289/.317/.513 and 17%, so the curveball (29% K rate) or even some righty-righty changeups (.583 OPS) might be a better option.

Look for the cutter and curveball (which I didn’t get into, but it had a .313 OPS and 47% K rate in 17 2H PA) to lefties, the four-seamer to righties, and the slider to both as key drivers if Stroman is going to be successful tonight. His excellent groundball rate helps him keep the ball in the yard at a great clip, but he’ll want as little contact as possible against this mashing team and those pitchers will be instrumental in delivering that.

Paul is the Editor of Rotographs and contributes to ESPN's Daily Notes. Follow Paul on Twitter @sporer and on Twitch at sporer.

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5 years ago

I didn’t understand why he was so highly ranked coming into the season. His strikeout rate wasn’t that high, he was coming off an injury, his track record is limited, and he pitches in the AL East. He did/does have high win potential and upside but to be taken as a low end #2 SP or high end #3 SP is a bit high. Next year he is likely to be a good player to target.

5 years ago
Reply to  OutOfTheBox

Obviously you are not familiar with the pitch comps… he should be better than Kershaw!