CHICAGO -- The Minnesota Twins put right-hander Tyler Mahle back on the 15-day injured list on Sunday, raising questions about their rotation during a difficult stretch.

Mahle left Saturday night's 13-0 loss at the Chicago White Sox because of shoulder inflammation. He was charged with four runs and five hits in two innings in his fourth start since he was acquired in an Aug. 2 trade with the Cincinnati Reds. His velocity on his four-seam fastball topped out at 88 mph in the second inning Saturday, well below his season average of 93 mph.

The 27-year-old Mahle was activated from the IL before the game after previously being sidelined by shoulder inflammation.

"I wouldn't want to close the book on his season,'' manager Rocco Baldelli said. "Is there an opportunity for him to come back and pitch? Maybe. But we have to learn a lot more before then.''

Mahle is 1-1 with a 4.41 ERA for the Twins and 6-8 with a 4.40 ERA overall this season.

Mahle's continued shoulder trouble comes on the heels of Sonny Gray leaving Friday night's game because of tightness in his right hamstring. Gray is slated to pitch Wednesday night against the AL East-leading Yankees, but that could change.

"The next thing for Sonny is for him to throw his bullpen, which will be in New York, and that's when I think we'll learn how his hamstring is doing,'' Baldelli said.

Infielder Jorge Polanco tested his ailing left knee before Saturday night's loss, but Baldelli said he is still experiencing some pain when he works out. Polanco was placed on the 10-day IL, retroactive to Wednesday, and infielder Jermaine Palacios was recalled from Triple-A St. Paul.

"He's able to go out there and field ground balls and throw to first,'' Baldelli said of Polanco. "He's altering his swing, just his swing in BP. It's not going to work. It's not a good idea, and I don't think it would be right for him to be playing." The Twins recalled left-hander Jovani Moran from St. Paul to replace Mahle on the roster. Moran was optioned on Saturday when Mahle was activated.

Minnesota had lost three in a row heading into the series finale in Chicago. The Twins began the day in second place in the AL Central, one back of the Cleveland Guardians and one ahead of the White Sox.

Baldelli said he wanted to wait before discussing the team's plan for its rotation with Mahle out. He also expressed confidence in his players' ability to respond to the recent adversity for the club.

"I think we've proven that time and time again, that regardless of what goes on, any elation or disappointment or anything like that, it really doesn't affect us,'' he said. "We just continue moving in the direction that we want.''

The Associated Press contributed to this report.