CHICAGO – Jorge Polanco took to Guaranteed Rate Field ahead of the game against the White Sox on Saturday to participate in warmups alongside the other Twins position players.

But the second baseman lagged behind as his teammates skipped and stretched ahead of him. And that seemed to be the ultimate decisionmaker for Polanco's immediate future.

The Twins placed him on the 10-day injured list, retroactive to Wednesday, shortly before the game because of left knee inflammation. Polanco has been dealing with patellar tendinitis there since an Aug. 15 game when he hurt himself sliding into home plate. He returned to game action by Aug. 19 and played fairly consistently until Tuesday, when he again left a game early because of continued knee pain.

Polanco had a magnetic resonance imaging exam when he initially suffered the injury, but it didn't show anything alarming.

"It looked like something, a little inflammation, something that should work its way out, and we were hopeful it would be a couple of days on the sidelines," Twins manager Rocco Baldelli said. "But obviously, he hasn't responded as quickly as we would have liked."

This is the second time this season — and also the second time in his entire career — that Polanco has been on the IL. He had avoided it since debuting in 2014, but a lower-back injury in June took him out for about two weeks. Polanco has hit .235 this season with 16 home runs, 16 doubles and 56 RBI.

The Twins are missing several key players to injury, including center fielder Byron Buxton, who is dealing with a hip injury as well as patellar tendinitis in his right knee. It's a tough time to be without the likes of him and Polanco, as the Twins have more than two dozen divisional games left in the last month of the season and are in a tight battle for the AL Central title and a playoff berth.

Jermaine Palacios was in the Twins clubhouse pregame Saturday, having joined the team on the taxi squad for just this scenario with Polanco. The shortstop is hitting .283 with the Saints this season and appeared in eight games this past May and June for the Twins when Carlos Correa was out with COVID-19.

To grant Palacios a spot on the 40-man roster, the Twins transferred catcher Ryan Jeffers to the 60-day IL. Jeffers has been out for 39 games while recovering from surgery on his broken right thumb.

Gray feeling OK

Friday starter Sonny Gray hurt his right hamstring on his final pitch of the third inning. And while he went back out for a fourth with his thigh wrapped up, Baldelli pulled him after out of precaution.

Gray said Saturday he felt good and doesn't foresee the injury holding him back from throwing his next bullpen or making his next start. Though he did admit it's a little early to really commit either way.

It's a similar area to the hamstring strain that put Gray on the IL in the first month of the season, but he said it isn't as severe.

"It was just one pitch that I threw, and it just kind of grabbed, and it was like, 'Oh, man,' " Gray said. "There were no lingering [effects from the April injury]. It hasn't been bothering me or anything."

The Twins only just regained their full starting rotation Saturday, with Tyler Mahle returning after overcoming his right shoulder fatigue. In the corresponding move, the Twins sent reliever Jovani Moran back to Class AAA St. Paul. That means Aaron Sanchez, who started twice in Mahle's absence, is still on the roster despite not really having a spot in the rotation to pitch anymore — Sanchez entered in relief of Mahle on Saturday.

Baldelli said Moran has pitched well, but he's the victim of having options left. And with Mahle likely making a shorter start Saturday because of his time off, the Twins needed Sanchez for extra length out of the bullpen.

"Whether that shows up [Saturday] or in the next couple of days, we don't know," Baldelli said. "But we're going to need [Sanchez]."