MINNEAPOLIS -- Right-hander Aaron Slegers will be called up from Triple-A Rochester to start on Wednesday against the Rays, replacing right-hander Dillon Gee as the Twins' fifth starter.

Gee will move back to long relief after struggling his past two starts, allowing four runs in four innings in Toronto and five runs over 2 2/3 innings against the Royals on Friday. Slegers has been pitching well at Rochester, striking out 10 batters in each of his past two starts while improving to 15-4 with a 3.40 ERA in 24 starts with the Red Wings.

"He's done what he's needed to do these last couple starts to have him be a consideration for us here, at least for this particular start," Twins manager Paul Molitor said. "I like how he matches up against that lineup, so we are going to go that direction. I talked to Dillon yesterday, just to make sure he understood the gratitude of him taking the ball for us when we took him out of a role he was very successful in."

Slegers also pitched well in his lone Major League start against the Indians on Aug. 17, allowing two runs on two hits over 6 1/3 innings. The 6-foot-10 right-hander has thrown a combined 154 2/3 innings between Triple-A and the Majors this year after throwing 145 1/3 innings at Double-A Chattanooga last year. So the Twins will be cautious with him going forward, although Slegers has said his goal is to reach 180 innings this season.

"I haven't talked to him about his goal," Molitor said. "Our conversations about that potentially being an issue, we don't feel it will be an issue at this time. We will have to monitor a guy who is getting to the area he hasn't gotten to before. I don't think there is a magic formula. It depends on the person a lot, too."

Worth noting

• The Twins activated catcher Jason Castro from the 7-day concussion list Sunday, but he was held out of the starting lineup. He took his ImPACT test on Saturday and was cleared by Major League Baseball to return before Sunday's game.

• Third baseman Miguel Sano 's left shin is beginning to feel better after a slow recovery, Molitor said. But there's still no timetable for his return.

"I think he's got a bit more energy, a little more excitement about the fact that he's feeling a bit better," Molitor said. "I just saw him a couple minutes ago in the weight room, and he's smiling. He's put some work in to try and keep himself as ready as he can be when he's given the clearance to start swinging the bat. I still don't have a timetable of when that will be."