Per Rob Bradford, Daisuke received an MRI on his right elbow after showing a complete lack of control in Monday's comeback win over the Orioles. While there have been no results announced as-of-yet, and it's possible that this move is simply a way to replenish the bullpen (with, say, Scott Atchison sent back to Pawtucket), it seems rather more likely that Daisuke is on his way to the disabled list.
If this is the case, then the Sox will find themselves in a bit of trouble. Michael Bowden is not stretched out to be a starter, and so is presumably only in Boston to fill a temporary bullpen role. Meanwhile, Felix Doubront, their primary starting depth in Pawtucket, is on the disabled list, if with a minor injury that should heal reasonably quickly. But forget Tim Wakefield not being an adequate spot starter, the Sox are actually out of warm bodies at this point. Andrew Miller hasn't shown any ability to throw strikes yet, and nobody else is really the kind of player a manager would be comfortable with starting against a major league lineup.
The Sox' rotation has been a big question mark to start the season, with only Beckett and Lester having any really consistent results. While the Sox were willing to put off making any sort of a move until the trade deadline came around, if Daisuke is indeed out for any period of time, injuries may now force the team into action.