ST. LOUIS — For the last seven weeks, the Chicago Cubs have navigated a rotation without their top two starting pitchers.

While they won’t be getting Justin Steele back following season-ending elbow surgery, left-hander Shota Imanaga is slated to rejoin the rotation Thursday when the Cubs activate him from the injured list to start against the St. Louis Cardinals to cap the teams’ first series of the year. Imanaga had a 2.82 ERA in eight starts before landing on the IL and will give the Cubs a boost.

Since Imanaga strained his left hamstring May 4 in Milwaukee, the Cubs have gone from 7 games above .500 to 15 over entering Monday’s series at Busch Stadium. Collectively, the Cubs’ starters produced a 4.46 ERA while Imanaga has been out, which includes the bulk outings by Ben Brown, Colin Rea and Cade Horton in the three games that had openers. It puts the group on the edge of the bottom third in ERA during that stretch, and their total 1.9 fWAR is 24th among starters.

Manager Craig Counsell was most impressed with one element of his team’s management of Imanaga’s absence: the rest of the rotation made all their starts.

“I don’t know if health seems like a compliment, but those guys taking the ball for the last seven weeks and staying healthy was critical for us and really important,” Counsell said Monday. “You never feel out of the woods when it comes to health or when it comes to depth or things like that, but us getting through this stretch and our starters taking their turn every time was massively important.

“And we lost our off days, we all know that in terms of the schedule and had rougher weather and all that stuff, so they’ve done a really nice job of that.”

Imanaga’s return means someone will get bumped out of the rotation, but Counsell didn’t reveal who that might be, instead stating, “We’ll figure that out Thursday.”

The Cubs’ bullpen added a fresh arm for the start of the Cardinals series by putting veteran Michael Fulmer on the 40-man roster and calling him up. Nate Pearson was optioned to Triple-A Iowa. Porter Hodge is also on the verge of joining the bullpen. Hodge, who has been on the IL since May 18, is in St. Louis, Counsell said, and the team is deciding when to activate him following four rehab outings in Iowa.

Shota Imanaga will return to Chicago Cubs for upcoming trip — but whose rotation spot will he take?

Fulmer, 32, had a 4.42 ERA in 58 appearances for the Cubs in 2023 but the right-hander needed Tommy John surgery and missed all of last year. It was the second Tommy John surgery of his career, with the first in 2019. He appeared in one game this season for the Boston Red Sox, surrendering three runs and four hits in 2 2/3 innings on April 14, then was designated for assignment and signed a minor-league deal with the Cubs. Fulmer posted a 2.96 ERA in 15 appearances (24 1/3 innings) with Iowa.

Counsell anticipates Fulmer will be used in multi-inning relief outings, similar to the way they have utilized right-hander Chris Flexen.

“The main thing was just getting game reps again and trying to pitch on a more consistent basis down there,” Fulmer said. “I got a couple innings a week at that, but obviously just trying to get built back up again and just get the quality reps in game and hopefully (I have) shown enough to get an opportunity up here.

“The whole rehab process with your second (Tommy John surgery), it’s it’s always everything goes slow, slow, slow, don’t do anything to impede your rehab process, but when you start throwing live BPs and start facing hitters again, it’s OK now you’ve got to go, go, go and it just doesn’t come back that easily. … Body’s feeling great, no complaints. Stuff is starting to come back a little bit, so I’m just excited.”