How Cubs’ Marcus Stroman is tapping into the best version of himself as a pitcher

MIAMI — Marcus Stroman’s sinker caught the inside edge of the strike zone and splintered Marlins leadoff hitter Jon Berti’s bat as he tried to battle it off.

After a first-pitch slider, Stroman had thrown Berti five consecutive sinkers to induce an inning-ending groundout in the third. Berti threw down his helmet as he ran through first base.

“I’ve put together a pretty decent second half, and I’ve thrown the ball really well, getting back to who I am as a pitcher,” Stroman said in a recent conversation with the Sun-Times. “And now, we’re starting to find how to adapt to make my starts even better. But I know who I am.”

Stroman’s sinker has been a focal point in that progression.

Stroman had a quality start against the Marlins in the Cubs’ 4-3 victory Wednesday, allowing three runs in six innings and striking out seven. His strong second half bodes well for the Cubs long past this rebuilding season. Stroman’s contract extends at least through next season, with a 2024 player option.

Two injured-list stints — the first when he contracted COVID-19 in May, the second when rushing back from the illness contributed to shoulder inflammation in June — disrupted the first half of Stroman’s season. But since coming back from the shoulder injury, he has tapped into two adjustments that have fueled his success.

One was a mechanical adjustment. Being sidelined for a month gave Stroman time to work on his balance point, a key Stroman credits pitching coach Tommy Hottovy with identifying.

“He’s had the ability to get away with maybe some mechanical inefficiencies because he’s a crazy-good athlete,” Hottovy said. “I was like, ‘All I’m asking you to do is get to this one position, and then let your athleticism go.’ ”

Watch Stroman’s delivery now. When he lifts his leg, he gets to a stable, slightly crunched position. From there, everything else falls into place, which is especially important for a pitcher who relies on feel as much as Stroman does.

That change helped improve the consistency of his delivery, which made his other second-half adjustment even more effective.

Early in the year, Stroman got away from his bread-and-butter sinker in favor of his four-seamer.

“A lot of times, when you look at things from an analytical perspective, it’s going to recommend a pitch that has unique movement profiles,” Hottovy said. “Because he has a low-slot sinker, and it has depth, with a low-slot four-seam, it actually is pretty unique.”

In his first game back from the COVID injured list, Stroman still was relying heavily on his sinker, and he held the Diamondbacks to two earned runs through five innings. But in his next three starts — against the Reds, White Sox and Cardinals — Stroman went to his four-seamer as much or more often than his sinker.

Before that nine-run start against the Cardinals, when health also was a factor, the four-seamer-heavy game plan produced results. Stroman threw seven scoreless innings against the Sox in one of his best starts of the season. But the emphasis on the four-seamer sparked other issues.

“My sinker started to cut,’’ Stroman said. ‘‘It wasn’t getting the same path. It wasn’t getting the same sink. I couldn’t throw it effectively. So everything played off there. And that’s all it was. It was a small adjustment. It was like, ‘OK, we still want to use this, but we need to get back to who you are, then implement it,’ which is what I’m doing now.”

Since returning from the 15-day injured list in early July, Stroman has gone back to attacking with his sinker and has posted a 2.87 ERA.

“In the end, when you come back full circle,” Hottovy said, “his ability to work on that four-seamer and then still come back and get locked in with the sinker, now he feels like he has confidence in all of it.”

Stroman still will feature his four-seamer against certain opponents. Look at his start in Toronto last month. His four-seamer usage jumped to 18.2%, according to Statcast, and he held the Blue Jays to one run through five innings.

On Wednesday, he threw only four four-seam fastballs.

“I’m still using the analytics because I’m seeing the holes in hitters’ swings,” Stroman said. “It’s just always remembering who I am as an athlete and pitcher.”