CLEVELAND -- Masahiro Tanaka has a partially torn ligament in his right elbow, and the New York Yankees hope their rookie sensation will be able to pitch again this season.
General manager Brian Cashman said Thursday night that Tanaka could return in six weeks, but didn't rule out the possibility of Tommy John surgery if the right-hander doesn't respond to a rehab program.
Cashman said Tanaka saw three doctors, including Yankees head physician Dr. Christopher Ahmad, and all three agreed that a six-week rehab program was the best option at this time.
"If we knew today that the best course of action was Tommy John surgery, despite the name and the amount of the investment, we would be doing Tommy John surgery," Cashman said.
The injury is a huge blow to a battered Yankees rotation already missing CC Sabathia, Ivan Nova and Michael Pineda to injuries. Tanaka had been a stabilizing ace in his first season since arriving from Japan.
Tanaka was placed on the 15-day disabled list Wednesday and had an MRI in New York, one day after his worst major league outing. He flew from New York to Seattle, where Ahmad was attending a conference.
Tanaka, who is tied for the major league lead with 12 wins, allowed five runs and 10 hits - both career highs - over 6 2-3 innings Tuesday night in a 5-3 loss to the Indians.
The All-Star is 12-4 with a 2.51 ERA in 18 starts, but has lost three of his past four outings.
"Certainly disappointed for our player, for our organization," Cashman said. "He's been an important piece. We have a tremendously gifted and tough player. We'll see how he responds."
The Yankees signed the 25-year-old Tanaka to a $155 million, seven-year contract in January after he had a standout career in Japan. New York also paid $20 million to his Japanese team, the Rakuten Golden Eagles, for his rights.
Tanaka has held together the Yankees' depleted rotation. Sabathia is expected to miss the rest of the season with a knee injury, and Nova had Tommy John surgery and won't pitch again until next year.
New York began the day three games behind first-place Baltimore in the AL East.
Elbow ligament-replacement surgery, commonly called Tommy John surgery, would almost certainly sideline Tanaka for at least a year.