Ugh. This isn't official yet, but it sounds like it might be soon -- Morton's rehab of his elbow injury has been put on hold, and it sounds like we'll soon know more about what the real problem is.
From the Pirates' perspective, this might actually be less problematic if Morton were a prospect. Unfortunately, he's already in his first year of arbitration. If he has Tommy John surgery, he might not return until the middle of next season, and he might not be at full strength until 2014. The Bucs would face the decision of whether to pay him millions of dollars in the meantime, only to have him be able to leave via free agency after 2014 anyway.
UPDATE: Morton has a torn elbow ligament and is "expected" to need Tommy John surgery.
UPDATE 6:39 p.m.: Morton has had the surgery.