Crain last pitched on Friday night against the Angels, when he gave up four runs in one-third of an inning. Twins general manager Bill Smith said that the shoulder issue first popped up during that outing.
An MRI on Crain's shoulder didn't reveal any structural damage, only slight inflammation. But the Twins felt the best decision this early in the season was to be cautious and give Crain plenty of time to get rid of the inflammation.
"We do not think this is a serious thing," Smith said. "The best thing for Jesse Crain is to shut him down from throwing for a week, and then we'll get him back on a throwing program next week."
The hope right now for the Twins is that Crain will be ready to come off the DL on Sunday, May 3 -- the first day he's eligible.
Losing Crain is the latest blow to a bullpen that's posted a 7.03 ERA in 39 2/3 innings this season.
In seven appearances this season, Crain is 1-0 with a 7.50 ERA. But prior to his outing on Friday, Crain had a 1.59 ERA and had allowed just one run over his first 5 2/3 innings.
For now, the Twins will use the eighth-inning-by-committee approach, pitching coach Rick Anderson said. Whoever is rested could get the call to set up closer Joe Nathan. The club has right-handers Matt Guerrier and Luis Ayala, who have both pitched in the role.
Mijares could also be an option for the eighth inning. The left-hander came to Spring Training as one of the favorites to compete for the setup job, following a strong September call-up from Double-A New Britain. But he reported to camp overweight and out of shape and then struggled with his command throughout the spring, posting a 9.90 ERA and issuing nine walks in 10 innings.
The Twins sent Mijares down with the message to get things right so that he would be the first pitcher called up when needed. The southpaw appears to have heeded the message, recording 6 1/3 scoreless innings in five appearances for Rochester. He has allowed just two hits with one walk and four strikeouts. Twins manager Ron Gardenhire said Sunday that the reports have also said that Mijares' velocity has increased to 93 mph, and that the pitcher has also been working hard to get back in shape.
"It's been a very small sample," Smith said. "He's only pitched a few innings, but he's throwing the ball better now, and he's the best one to come up and help us."