Following an examination conducted by Dr. William Raasch, LHP Chris Capuano was found to have a tear of the ulnar collateral ligament in his left elbow.  

Capuano and the team will use the next couple of days to evaluate the medical options.

Great downloadable document that explains the injury for a pitcher.  Excerpt:

Extreme valgus forces are generated across the medial aspect of the elbow during overhead throwing activities, such as pitching, throwing a javelin, and serving a tennis ball. The ulnar collateral ligament (UCL), located on the medial aspect of the elbow, is the primary structure responsible for resisting these valgus loads. The repetitive motions concentrate tremendous amounts of stress on the UCL that may eventually result in damage to this structure. Injury to this ligament does not commonly lead to symptomatic elbow instability in the general population. However, overhead throwing athletes have a unique dependence on this ligament, and they may require operative treatment in order to stabilize their elbow after injury and allow them to return to competitive athletics.

Reconstruction:

Surgical reconstruction of the UCL is indicated for competitive athletes who have failed at least 3-6 months of nonoperative management. The patient must understand that there is a lengthy recovery period as well as an intensive postoperative rehabilitation that is required.

Patients are kept immobilized in a posterior splint for 1-2 weeks. A hinged elbow brace can then be used if so desired by the surgeon. Shoulder range-of-motion exercises are also
begun at this time. At 6 weeks, an elbow-strengthening program is started with the use of light weights. A progressive throwing program is instituted at 3-4 months, under strict
supervision. Not until 9 months after surgery can the athlete return to full throwing, and observation is continued for an additional 3-4 months. It will take most athletes 12-18
months to return to their preinjury level of function.