The Twins website is reporting that Guerrier will join the Rock Cats tomorrow in Erie, PA to begin his rehab assignment, and probably will only be with the team for a little over a week. The site is projecting that Guerrier could be ready to rejoin the team in time for a series that begins on July 28.
This is good news, because it means that Guerrier, who had been having a very solid season before the injury, will be able to replace Willie Eyre in the bullpen. I assume that this means the Twins won't bring up Chris Heintz to replace Eyre anytime soon, because they'd be sending him right back down again in a week.
The more interesting question is what the Twins do if Guerrier returns and the Twins then decide to cut down to 11 pitchers. The untouchables are, of course, Joe Nathan, Juan Rincon, and Dennys Reyes. Willie Eyre is going to be sent down when Guerrier is called back up, and Guerrier won't be going anywhere. That leaves Jesse Crain, Kyle Lohse, and Pat Neshek.
For me, there is no question here. The Twins only use Lohse in blowout situations, and he should be gone by the time the trade deadline goes, as hopefully some contender will get desperate and make a deal to pick him up. To send Neshek down after giving him a chance to pitch in the 7th inning of a one-run game doesn't seem to make any sense. And if the Twins stuck with Jesse Crain when he was struggling early this season, they aren't going to send him down now that he's regained his form.
Of course, this may not even be a consideration. So long as the Twins stick with 12 pitchers, it isn't a question. But sometime in August, we may be considering this question, especially if aches and pains keep more players out of the lineup on an everyday basis, Kubel-like.