Over his last seven starts, Marcus Stroman hasn’t really looked like the All-Star he was early in the year.

Wednesday afternoon, there was a bit more clarity behind some of his struggles. The Cubs placed the righty on the 15-day IL with right hip inflammation, retroactive to Tuesday. To replace him on the active roster, the Cubs activated José Cuas. Cuas was acquired from the Royals on Monday for outfielder Nelson Velázquez.

Stroman did not specify when he initially started feeling the hip issue but admitted it’s been bugging him for “a bit now.” He received a cortisone shot in the hip on Wednesday and will take a couple days off before getting on a program to strengthen the area.

“Just progressively got more pinchy to the point where it’s really uncomfortable to just sit and to be in a seated position, where kind of my hip is kind of in that flexion which kind of relates to my delivery and my leg,” Stroman said. “So it all kind of correlates. It just got to the point where I was doing too much with my upper body and trying to do so much without having a lower half. I just felt it becoming very problem-some so just address it now and go from there.”

Stroman had his second-shortest outing of the season on Monday, going just 3 innings against the Reds, allowing 6 runs on 6 hits as the Cubs dropped the opener to Cincinnati 6-5. He hasn’t made it past the 4th inning in his last three starts and has a 15.30 ERA over 10 innings in that time.

He was a pivotal piece of the Cubs rotation over the first three months and one of the best pitchers in baseball in that span. In his first 16 starts, Stroman had a 2.28 ERA and a .191 batting average against in 98.2 innings.

“Beyond frustrated [at the recent struggles] because I do so much in between starts to get right and to focus on things,” Stroman said. “When everything you’re doing is not fixing it, I feel like I just had to go to the root of the problem rather than trying to get around it.

“I’m not even slightly worried. I know after this, I’m gonna feel strong. I’m gonna get on the program with the trainers and I should be right to where I was.”

The Cubs are hopeful Stroman will only miss 1 start as they have a bunch of off-days coming up (Aug. 10, 14 and 17). He is eligible to return on Aug. 16.

“I think it was just best for everybody,” David Ross said. “Stro can get back into a sound mechanical delivery and him feeling good, working on a few things and also making sure he’s completely healthy when he does step foot on the bump again.”

In his absence, the Cubs could turn to Hayden Wesneski to fill his spot in the rotation. Wesneski was called up last week to serve as an opener for Drew Smyly. Smyly, Wednesday night’s starter against the Reds, is back in the rotation and Wesneski was being stretched out as a starter in Iowa. Javier Assad is also an option, though he has settled into a nice groove as a long reliever in the Cubs bullpen.

Cuas has appeared in 92 games over the last two years, pitching to a 4.08 ERA in 79.1 innings. The righty had a 27.1% strikeout rate this season with Kansas City. He should provide depth to the Cubs bullpen going forward.