CLEVELAND -- The Twins' starting pitching depth took a hit on Thursday, as right-hander Aaron Slegers was pulled off his rehab assignment after experiencing shoulder discomfort during a bullpen session.
Slegers, who was placed on the 10-day disabled list with right shoulder inflammation on July 15, made one rehab appearance with Triple-A Rochester on Saturday but felt the symptoms again a few days after his start. An MRI exam revealed no structural damage, but he's going to be shut down with no timetable for his return.
"We're going back to square one with him," Twins manager Paul Molitor said. "He made that start, and he went out to do a bullpen, and he was feeling that pinching sensation in the back there, posterior."
Slegers, 25, has made three appearances (two starts) with the Twins this season, posting a 5.68 ERA. But he's fared well at Triple-A Rochester over the last two seasons, posting a combined 3.54 ERA with 176 strikeouts and 48 walks in 233 2/3 innings.
There's a chance Slegers could return later in the season, but it depends on how the 6-foot-10 right-hander's shoulder reacts over the next few weeks. Triple-A Rochester's season ends on Sept. 3, so there are roughly four weeks left for him to get back to making Minor League rehab appearances.
With Slegers out, right-hander Fernando Romero moves up the pecking order at Triple-A with lefty Stephen Gonsalves behind him. Left-hander Adalberto Mejia has been pitching well as Minnesota's fifth starter but suffered a left wrist strain on his final pitch against the Indians on Tuesday.
Mejia, who held Cleveland to one hit over five scoreless innings, played long toss on Thursday and will throw a bullpen session on Friday to determine if he's healthy enough to start on Sunday. If not, Romero is the top candidate to start Sunday.
Worth noting
• Outfielder Robbie Grossman, on the DL with strained right hamstring suffered Sunday, will join the Twins in Detroit to continue his rehab because Target Field will be hosting a concert this weekend. Grossman is making good progress, according to Molitor.
"He's increasing activity daily," Molitor said. "Took some light swings off the tee Wednesday. It's mostly about agility, bike, treadmill, manual stuff he's working on trying to get that back. Considering it was a low-grade, lower hamstring injury."
• Center fielder Byron Buxton, on the Minor League DL with a left wrist sprain, hit in the cages on Tuesday and Wednesday before progressing to taking batting practice outdoors on Thursday. Barring a setback, Buxton remains on track to rejoin Rochester by next week, potentially early in the week if all goes well.