Masahiro Tanaka was diagnosed Thursday with a partially torn ligament in his throwing elbow, but the Yankees are hoping his season is not over.
The rookie pitching star from Japan will not undergo surgery, at least not yet.
Tanaka, who's tied for the major league lead in wins with 12 and was named to the All-Star team, is set to begin a rehab program.
General Manager Brian Cashman said Tanaka could return in six weeks, but if rehab doesn't work, he may need Tommy John surgery, which would keep him out for him for about a year.
Tanaka is the fourth member of the Yankees rotation now sidelined with an injury.