BOSTON -- A right leg bone bruise initially expected to keep Mark Teixeira out a maximum of 10 days already has sidelined the Yankees first baseman significantly longer than that.

The news didn't get any better Tuesday.

Teixeira underwent a second MRI on the affected area in New York, with the test showing "the extent of the bone bruise is more than we thought," manager Joe Girardi said, adding the veteran will be on crutches for at least "a few days."

The positive news is that the MRI did not show a fracture, but that was all on the good-news front as it is clear Teixeira is out indefinitely.

Asked for a timetable for the 35-year-old's return, Girardi could not offer one.

"I have no idea, I really don't," Girardi said. "Because I would have thought he would have been back by now. Obviously, I was wrong. You just don't know how long it's going to take."

Teixeira left the Aug. 17 game against the Twins after fouling a ball off an area below his right knee. He underwent an X-ray, CT scan and MRI the next day and was given the week to 10 days time frame as a worst-case scenario.

"I think it's good news that there's not something broke or that situation," Girardi said. "But the frustrating part is we're not sure how long he's going to be out."

Lefthanded-hitting rookie first baseman Greg Bird has filled in for Teixeira and done reasonably well, his rough game Monday night here notwithstanding.

On Monday GM Brian Cashman all but dismissed the possibility of Alex Rodriguez getting some time at first with Teixeira out, saying Chase Headley would be the far better option.

But Girardi obviously feels differently.

"I think you have to really talk about it now," Girardi said. "I think our hope was that when we left on that road trip [which started in Atlanta last Friday] that you would have Tex back by the time we got home, or even on the road trip. But now I think you have to think about it because you're going to see lefthanders. There's lefthanders in our division and we're seeing a lot of division opponents in the next 32 games, so I think you have to start debating the idea."