The Cardinals gave Kwang Hyun Kim nine days of rest between his last two starts, but the lingering left elbow inflammation he experienced during that recovery period forced the club to put its southpaw on the injured list on Monday.

Manager Mike Shildt said prior to Tuesday’s series opener in Pittsburgh that Kim isn’t running into any issues while he’s on the mound, but the downtime in between has become problematic. Imaging has not uncovered anything structurally wrong.

“Structurally everything checks out, but [he] just hasn't been able to recover and be able to carry the load of every five or six days right now,” Shildt said.

Right-hander Daniel Ponce de Leon was activated off the IL on Monday in Kim’s place; Jack Flaherty will return from his own injury on Friday and take Kim’s spot in the rotation.

On Saturday, after he returned from his rest period to throw 83 pitches without inhibition against the Royals, Kim said he felt his elbow barking a little bit two starts prior -- on July 22 against the Cubs -- but the club believed some extended downtime could get rid of the issue.

Instead, Kim was handed his third IL stint of the season, after back ailments delayed his start to the season and later forced him to miss a start in June.

If there's any silver lining, it's that Kim's shelving created an opening in the rotation, which Flaherty will fill. Miles Mikolas is also expected to return after one more rehab outing.

The club is not ready to label Kim’s role for when he returns, but the fact that he began his Cardinals tenure last season in the bullpen, paired with his season-long difficulty to pitch deep into games, may make him a candidate to slot back into the ’pen.

Kim, in the final year of his two-year contract, has been as dependable as any Cards starter this season, but St. Louis has been facing the reality of a rotation squeeze since it acquired Jon Lester and J.A. Happ at the Trade Deadline.

Ponce de Leon, meanwhile, returns after a lengthy stay on the IL with his second right shoulder injury of the season. He appeared in four rehab starts and and can provide multiple innings out of the bullpen, though Shildt said he doesn't see him as a definitive long-relief option.