"It took a little bit of time but I finally received some clarification on Sheet's injury. Yes, it is the teres major muscle, and not the latissimus (lat) dorsi muscle he tore last season. Before Sheets suffered the injury last season, his teres major muscle and lat muscle inserted (connects to the bone) in two different locations. In most people, they blend as one muscle just before the insertion point. After Sheets suffered the injury last year, both muscles healed and connected just before they inserted to the bone.
His current injury is a slight strain of the teres major muscle in that area and is caused by some overuse this spring. These muscles are 'relearning' a bit because of the two muscles 'merging' close to the bone. The team's medical staff is being diligent with Sheets, focusing on strengthening of the muscles in this area to help prevent further problems. After digesting this news we're not as concerned about this injury and Sheets' future. We'll get a better idea how far back he is when he resumes throwing curveballs, the pitch that caused the strain. The Brewers realize he's their pitching franchise and because of that viewpoint, it wouldn't come as a surprise if he starts the year on the disabled list. This is more of a precaution than any other reason." DR. HQ, INJURY ANALYST
Rick Wilton, March 24