How Matt Swarmer’s unique slider is bringing the 28-year-old Chicago Cubs rookie big-league success

Chicago Cubs rookie Matt Swarmer knows his high extended leg kick is reminiscent of another big-league pitcher.

“People always ask me, ‘Do you get it from Bronson Arroyo?’” Swarmer told the Tribune. “I just developed it on my own.

“But I like to tell people it’s from Arroyo,” he added, laughing, “because I don’t know how to explain it sometimes.”

The 28-year-old right-hander is making the most of his unexpected call-up this week. Days after Swarmer’s big-league debut Monday, he was still in shock as the magnitude of reaching the majors continued to sink in for the former 19th-round pick.

And after Saturday’s 6-1 victory in Game 1 of a doubleheader against the St. Louis Cardinals — his first win in his second career start — Swarmer again searched for words.

“Oh, man, it’s incredible,” Swarmer said Saturday. “I’ve always thought about just being here, and now I’m competing with the best guys. Oh, it’s so cool. I’m just living in the moment right now.

“I always watched those guys on TV, and now to have a chance to face them, it’s really special in that moment. I have to soak it all in.”

In both starts Swarmer held the opposition to one earned run in six innings while combining for 11 strikeouts and three walks. At the root of his success is a nasty slider. He generated 13 whiffs with his slider Saturday after producing 10 on Monday. Another 12 sliders over the two starts resulted in called strikes.

“When he’s at his best, he has a unique slider — just the way it looks when it comes out of his hand, the way it moves,” pitching coach Tommy Hottovy told the Tribune. “A lot of times you’ll see guys have two pitches that are power pitches, but he also has the ability to move that slider around and locate it where he needs to. As long as he can command those two pitches and move them around, you can do a lot of really good things.

“Sometimes guys get here and they try to do too much. He’s not a guy that is going to try to do more than what he knows he can do.”

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Swarmer relies on two pitches — a four-seam fastball and slider — at a frequency that’s uncommon for major-league starters. Through two starts with the Cubs, they accounted for 97.2% of his pitches.

But it’s his ability to manipulate his slider, essentially creating two pitch shapes, that makes the pitch so effective. When Swarmer is looking to put a hitter away down in the zone or even just trying to get the pitch over the plate, he will take something off his slider and sometimes get more around the baseball. If he stays on top of the ball with his slider grip, it creates sharper vertical break.

A key to his success is keeping the same arm angle when utilizing each slider type while also tunneling it off his fastball. Swarmer initially used his slider grip in 2018 but lost it during the 2019 season. It took until last July to finally get it back to where he wanted it.

“For hitters like this, you have to be very selective where you’re going to throw because they’ll hit it if it’s around the plate,” Swarmer said.

The success of his two-pitch mix two games into his big-league career doesn’t mean he is abandoning the development of a third pitch, a changeup. Swarmer knows he will need to incorporate the pitch more as teams build a scouting report against him. Of the 178 pitches he threw in his first two starts, only five were changeups.

Swarmer believes he might have found a changeup grip that works for him, but he continues to tinker.

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“The only way I’ll know if it’s good is if I throw it to hitters,” Swarmer said. “And if I don’t, you basically won’t know until you face hitters like these.”

It comes down to finding a low-leverage situation or identifying the right hitter to deploy the changeup against, Hottovy said. Before the National League adopted the designated hitter, the pitcher spot used to be a good opportunity to work in a developing pitch.

“On the flip side of that, we want guys who attack with their strengths,” Hottovy said, “and the one thing that pitchers do have an advantage with is the hitter doesn’t know when we’re going to break out a new pitch.”

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Swarmer’s stellar first two starts — against division rivals no less — serve as a great jumping-off point for taking the next steps as a big-league pitcher. For Swarmer, that entails locking in on all facets: honing his changeup, controlling the running game and in-game situations and harnessing the strategy side.

In the minor leagues, a lot of success can come from just executing pitches and getting outs. With the Cubs, Swarmer will need to prove he can work through a lineup and mix his pitches well enough to keep hitters guessing.

But perhaps most importantly, Hottovy wants Swarmer to keep having fun and being himself because that’s a big part of what has made him so good.

“I worked so hard for this,” Swarmer said. “In the minor leagues, you have to just be true to yourself and say, hey, if you just keep putting in the work, you’ll have a chance to be successful one day. I just kept competing and I thank God I’m here.”