BOSTON -- Add another one to a list of key injuries for the New York Yankees.
Yankees manager Joe Girardi expects leadoff hitter Brett Gardner will be out for a lengthy stretch and possibly the rest of the regular season.
Girardi made the announcement before New York opened a three-game series with the Boston Red Sox at Fenway Park on Friday night.
Gardner left Thursday night's win in Baltimore with the injury, which Girardi said is a "Grade 1 strain in his rib cage." He's batting .273 with eight homers and 52 RBIs and a big part of New York's injury-ravaged offense.
"He's going to be out a while," Girardi said. "Rib cages don't heal real quick. It's not like it's just a few days. Is it possible it could be the rest of the year? Yeah."
It's the latest in a season filled with injuries for the Yankees, who entered Friday one game back in the AL's wild card chase.
"I'm almost at the point where I don't think it surprises our guys anymore," Girardi said. "I don't want to diminish how important guys are to us, but we've kind of gotten used to it. A guy comes back, a guy goes down. That's kind of how it's been all year long."
Mark Teixeira was on the DL early in the year before being lost for the season with right wrist surgery. Derek Jeter, who missed most of the season recovering from left ankle surgery, was lost this week for the remainder of the season with soreness in the repaired ankle. Outfielder Curtis Granderson, infielder Eduardo Nunez, third baseman Alex Rodriguez and outfielder Jayson Nix are among a number that have missed significant time with injuries.
"It's a big loss," said Girardi of Gardner. "You know we've had to overcome a lot through the course of this year. People are going to have to step up during his absence. He's been really good for us. He's been really good offensively, defensively and getting us off to good starts."
But the Yankees still remain in the hunt.
"It's a club that doesn't feel sorry for themselves," Girardi said. "They understand injuries are part of the game and you have to overcome them."
Girardi said he hopes to use Gardner as a pinch-runner, but said it won't happen at least until the end of the next series in Toronto.