In the wake of Marcus Stroman’s mysterious injury, the Cubs knew they would need to go back to a 5-man rotation.

The team had been taking advantage of all the recent off-days to roll with a 4-man rotation for the most part while Stroman initially was on the IL with a hip injury. But now he will be out for at least several more weeks with a rib cartilage fracture and the Cubs will pivot and insert Drew Smyly back into the rotation.

Smyly will get the ball Tuesday in Detroit with Javier Assad pitching Monday and Jameson Taillon taking the hill for the series finale Wednesday afternoon.

The Cubs could have turned to rookie Hayden Wesneski but would prefer to roll with the veteran Smyly in the rotation moving forward.

“Just hoping he can build off a couple performances out of the ‘pen,” David Ross said before Sunday’s game. “I think there’s some analytic numbers that point toward leading towards him. There’s some experience leading towards him. I think there’s value of Hayden out of the ‘pen.

“I think there’s a multitude of reasons to lean on [Smyly] and be able to have him as a guy that’s a staple in our rotation. Obviously he has to perform well. Every performance matters and wins matter.”

Smyly began the season in the rotation and pitched well, sporting a 2.60 ERA and 5-1 record through his first 10 outings. But he struggled to the tune of a 6.65 ERA over his next 9 starts and the Cubs opted to bring Smyly out of the bullpen for back-to-back games against the Cardinals in late-July.

The Cubs then reinserted Smyly back into the rotation but he surrendered 12 runs in 9.2 innings across a pair of starts to begin August, prompting another move to the bullpen.

Smyly has found success recently as a reliever, with 3 shutout innings, albiet in a very small sample size. Ross believes the shutdown innings out of the bullpen can have a positive mental effect on Smyly and serve as a good lesson for the veteran southpaw to be aggressive and attack hitters.

Though he has spent the last couple weeks in the bullpen, Smyly has been able to maintain his conditioning and is still built up to provide some length Tuesday night.

If he’s not, the Cubs could always piggyback Wesneski out of the bullpen and have him face a lineup likely loaded with right-handed hitters.

“Trying to look at every option when you have a couple guys you could lean on in that spot,” Ross said. “We could piggyback it if we need to but I think the veteran component plays a small role in it. And then the consistency — consistency in the rotation, somebody that you know has been in there and knows what it’s like, knows how to prepare and feels like gives you a really good chance to win.”

Smyly is a 10-year MLB veteran who has pitched in the playoffs and appeared in a pair of World Series (2012 with Detroit, 2021 with Atlanta). He knows what it takes to compete in the middle of a pennant race as the Cubs began Sunday 3 games behind the Brewers in the division and tied for the final NL Wild-Card spot.

The Cubs also have a lot of faith in Smyly to turn things around. He had success to start this season and he also went on a run right around this time last year.

In his final 9 starts of the 2022 season, Smyly had a 2.28 ERA that helped prompt a reunion with the team over the winter.

“I thought he was excellent last year at the end of the season, really pitched well for us,” Jed Hoyer said earlier in the homestand. “Maybe started a little bit before the Field of Dreams game, he got on a real roll and then pitch great at the beginning of this year.

“Obviously he’s had a downturn and we changed his role a little bit, but we’re gonna need him to make a lot of a lot of big appearances, a lot of big starts. The hope is that maybe a little bit of rest and kind of working on things right that he can turn right back around.”