Nova was examined by team physician Dr. Chris Ahmad at New York Presbyterian Hospital and underwent an MRI, which revealed the injury. The Yankees said they expected the injury to "heal without complications" during the winter.
Nova, a 16-game winner in his first full season as a starting pitcher, took the loss in the decisive game, won by the Detroit Tigers 3-2 at Yankee Stadium.
Afterward, Nova, 24, said he did not experience any pain in the arm during the first inning, but felt it on virtually every pitch in the second, during which he allowed a leadoff double but retired the next three hitters, including striking out Ramon Santiago to end the inning.
"I just made two mistakes in the first inning, and in the second inning, they take me out," a downcast Nova said after the game. "It's hard when you don't feel good, and you gotta come out of the game so quick. And we gotta go home now. Nobody can feel good about this."
Wallace Matthews covers the Yankees for ESPNNewYork.com.