Moss traveled to Vail, Colo., late last week, expecting to undergo a microfracture procedure. An end-of-the-season MRI had revealed cartilage being separated from the bones in his left knee, and both Dr. Patrick DeMeo in Pittsburgh and Dr. Richard Steadman in Vail agreed that a microfracture procedure would be the best course of action.
Such a procedure typically requires two months of rest, followed by four to six months of rehabilitation.
On Friday, however, Steadman did a diagnostic scope on Moss' knee and reported back to the Pirates that he felt arthroscopy was the best course of action at this time. A scope involves a much smaller incision than open surgery and involves a much shorter recovery time.
In this type of procedure, a surgeon removes or repairs damaged tissue with surgical instruments inserted through small incisions in the knee.
According to general manager Neal Huntington, Moss has already begun his rehabilitation and should be ready for all activities when camp opens next February. The club will then continue to monitor Moss' knee with periodic evaluations throughout the season.
This change, of course, is good news for the Pirates, who had been counting on Moss to man one of the two corner outfield spots on Opening Day.
After coming to Pittsburgh in the July 31 trade that sent Jason Bay to Boston, Moss hit .222 in 158 at-bats. The outfielder showed some power in hitting six homers in the season's two final months and finished with 23 RBIs, though expectations going into next season will be much higher.
He missed the final six games of the season after his knee injury was identified.
Jenifer Langosch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.