Greene had surgery to fix what Tigers head athletic trainer Kevin Rand called a pseudoaneurysm in the circumflex artery in his throwing shoulder. As Greene explained on Twitter, the issue was causing blood clots in his index and middle fingers. With blood flow curtailed, Greene suffered from numbness in his fingers. Greene left a promising start at St. Louis after five scoreless innings with numbness in his right ring finger, but that was diagnosed as ulnar neuritis.
Greene didn't miss a start in that stretch, but his pitching began to deterioriate. He was optioned to Triple-A Toledo in June, made five starts in a Mud Hens uniform, rejoined the Tigers in mid-July for about a month, then made two more starts for the Hens before a recurrence landed him on the Major League disabled list. An ensuing examination revealed the aneurysm symptoms.
The procedure ended Greene's season with a 4-8 record and 6.88 ERA in 18 appearances for the Tigers, having allowed 103 hits over 83 2/3 innings. Considering his early-season dominance, having allowed a lone earned run on 12 hits over 23 innings in his first three Tigers starts, the debate lingers over how much of his struggles were injury-related.
When Greene is on, he's a hard-throwing sinkerballer, His average fastball velocity dropped from 93.1 mph with the Yankees in 2014 to 91.7 mph with the Tigers this year, according to Fangraphs. His ground-ball rate dropped from 50.2 to 43.8 percent, and his strikeout rate was the lowest of his professional career.
Greene resumed physical activity shortly after the surgery, but he couldn't throw for about two months. That puts Greene right on his projected recovery schedule. He's expected to be ready for Spring Training, where the Tigers hope to see what he can do in fully healthy form.
Greene is expected to compete for a rotation spot with fellow young hurlers Daniel Norris, Matt Boyd, Michael Fulmer, Kyle Lobstein and others. General manager Al Avila has also left open the possibility Greene could be moved into the bullpen to help there.
Jason Beck is a reporter for MLB.com. Read Beck's Blog, follow him on Twitter @beckjason and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.