Center fielder Mike Cameron has a lower abdominal strain, and the hope is that he can return within the next two to three weeks.
Left fielder Jacoby Ellsbury, who has a left rib contusion, could return as soon as next Tuesday night in Toronto. His DL stint was made retroactive to April 12, the day after he had a nasty collision with third baseman Adrian Beltre.
In the case of Cameron, the Red Sox are just happy to know what the injury is. He had excruciating pain in Minneapolis on Thursday, and it was later revealed that he had kidney stones. After passing the stones on Friday, Cameron somehow returned to the lineup on Saturday and also played on Sunday.
But he started feeling abdominal pain again, and the initial thought was that he might have more kidney stones. Cameron spent most of Monday at Massachusetts General Hospital, where the determination was made that he had the lower abdominal strain.
"It was obvious something was bothering him. It's kind of scary when you don't know what it is," said Red Sox general manager Theo Epstein. "The coincidence of having the kidney stone at the same time -- in the same general area -- made it more difficult to diagnose and cast some uncertainty over it. We feel good that now at least there's a diagnosis. That said, it's tough news.
"It's not what we were looking for and it's a tough break for Mike starting his Red Sox career. It's obviously something that's been bothering him and affecting his play a little bit. It might date all the way back to Spring Training, that groin thing he felt towards the end. It could be related -- the groin meets the pelvic bone meets the abdomen is really what's at issue here. We just need to knock it out and make sure when he comes back, he's not restricted in any way and can play 100 percent. We're going to treat it conservatively and make sure he gets all the way better."
If he had continued to play, Cameron would have risked a complete tear, which would have meant surgery and had a lengthy recovery process. The Red Sox are confident that they caught the injury in time to avoid surgery, and that rest and rehab will do the trick.
"My stubbornness sometimes gets in the way," said Cameron. "The way it was laid out, I'll take these days off -- five or seven days of doing nothing, let the body heal on its own, see where I'm at. If it heals, then I'll start the process of getting back ready while I'm on the DL. If I don't abide by it, it could make it worse in the sense where I would have surgery."
Outfielder Josh Reddick, a prospect the Red Sox think highly of, will get plenty of playing time, at least until Ellsbury returns. Reddick, who spent multiple stints with Boston last year and had a terrific Spring Training, was recalled from Triple-A Pawtucket before the game. Jeremy Hermida will continue to play regularly as well. The club also promoted Darnell McDonald from Pawtucket. He will give manager Terry Francona a right-handed bat and some bench depth.
The Red Sox waited as long as they could with Ellsbury before putting him on the DL. But after taking batting practice before Tuesday's game, the leadoff man knew that he wasn't ready to play yet.
"I've taken tee work in the past, and today was kind of the last day that we had to make a decision -- either we're going to try to push it and see how it feels and hopefully it feels a little bit better," Ellsbury said. "I tried to push it out there and it wasn't working, so we had to make a decision one way or the other."
Once Ellsbury returns, he can play center field until Cameron is ready to come back.
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.