TAMPA, Fla. (AP) — Yankees reliever Joba Chamberlain is set to test a strained muscle on his upper left side.

LISTEN: Joe Girardi & Joba Chamberlain discuss the injury

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New York manager Joe Girardi said the right-hander will play catch for the first time in four days Thursday. An MRI this week found that Chamberlain has a mild strain.

“First step is let him feel good playing catch and go from there,” Girardi said before Wednesday night’s game against Baltimore. “Anytime, I think, you hear a strain, that’s bad news. It’s not what you want to hear, but right now, he feels good. Throwing is different than doing things in the training room.”

Girardi is hopeful Chamberlain will be ready for opening day.

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“The bottom-line is, we want the player healthy,” Girardi said. “But we’ll be smart about it. If he plays catch and doesn’t feel great, we’re not going to say, OK, you’ve got to get on the mound.”

Chamberlain experienced a cramp-like feeling while pitching in a game last Friday. He continues undergoing treatment.

“I feel fine,” Chamberlain said. “I have no soreness. I’d rather take care of it now than have it linger into the year. Error on the side of caution.”

NOTES: Girardi said no decision has been made on whether Phil Hughes or A.J. Burnett will be second in the rotation behind ace CC Sabathia. … Freddy Garcia, Ivan Nova, Bartolo Colon and Sergio Mitre are competing the final two rotation spots.

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