NEW YORK -- There was disappointment in Masahiro Tanaka's eyes on Wednesday morning, according to manager Joe Girardi, one day after the Yankees right-hander learned that he will miss at least a month with a strained right forearm and tendinitis in his right wrist.
For the moment, the Yankees believe that Tanaka's current injury does not represent a precursor to Tommy John surgery, but they recognize that possibility. Tanaka will refrain from throwing for seven to 10 days and is not expected to travel with the team.
"Any time you have to shut a pitcher down, there's concern," Girardi said. "With what happened last year, I can't tell you if they're related or not, but you're going to think about it. You're going to think about a lot of different scenarios. Let's just keep our fingers crossed and hope it's not much, but we'll deal with it either way."
The Yankees plan to keep right-hander Chase Whitley in the rotation, coming off a season debut in which he held the Rays to one run over five innings and picked up the win in a 4-2 victory. To replace Tanaka on the active roster, infielder Gregorio Petit was recalled from Triple-A Scranton/Wilkes-Barre.
"It's going to be tough," Yankees left-hander CC Sabathia said. "It's going to be up to us to pick up the slack. Hopefully he comes back healthy and ready to pitch."
There could be additional help on the horizon. New York also has left-hander Chris Capuano and right-hander Ivan Nova rehabbing and aiming to rejoin the club in late May and early June, respectively. By that time, Tanaka could be back on the big league mound, but perhaps not.
"The one thing I've tried to stress to our starters is, 'Don't try to make up for someone else's absence,'" Girardi said. "'Just do what you can do.'"
Team physician Dr. Christopher Ahmad recommended that Tanaka be placed on the 15-day disabled list after an MRI revealed the Grade 1 strain in his forearm, which was said to be asymptomatic. Yankees general manager Brian Cashman said that the MRI showed no changes to Tanaka's right elbow.
"I think you're probably a little bit more concerned with the forearm strain than the wrist," Girardi said. "He didn't feel anything [in the elbow], but you're always a little bit concerned when you're dealing with the forearm."
Girardi said that he was "shocked" when Tanaka reported the discomfort, coming off a bullpen session Sunday that pitching coach Larry Rothschild had delivered positive reviews about.
Tanaka was scheduled to start against the Rays on Wednesday, but Girardi said that he had to find right-hander Michael Pineda on the training table Tuesday afternoon and tell him to prepare for the start instead.
"It's just kind of out of the blue," Girardi said.
Tanaka's injury has prompted commentary that the Yankees should have dispatched the hurler to have Tommy John surgery after sustaining a partial tear of his ulnar collateral ligament last July 8 in Cleveland.
Following that injury, Tanaka was examined by Ahmad, Los Angeles Dodgers team doctor Neal elAttrache and Mets team physician David Altchek. His results were also sent to James Andrews for consultation, and all four doctors recommended the Yankees should rehabilitate Tanaka's injury using platelet-rich plasma injections rather than rush into surgery.
"I am a manager. I am not a doctor, so I don't understand the mechanics of all that," Girardi said. "As I said yesterday, there's going to be speculation. Are they related? I can't tell you that. I don't know -- could be, it may not be. It could just be something came up from his bullpen. Who knows? The thing is, we've got to deal with it, and we will."
Bryan Hoch is a reporter for MLB.com. Follow him on Twitter @bryanhoch, on Facebook and read his MLBlog, Bombers Beat. This story was not subject to the approval of Major League Baseball or its clubs.