By Peter Abraham, Globe Staff

BALTIMORE ' Red Sox outfielder Cody Ross will be placed on the disabled list on Tuesday with a fractured navicular bone in his left foot.

Ross was in Boston today for an MRI on his foot, which was injured on Friday when he fouled a ball off it in Philadelphia. Although an initial x-ray showed no breaks, a further examination showed the fracture.

Bobby Valentine did not offer a timetable on when Ross might be able to return other than it would be "less than a couple of months."

Dustin Pedroia fractured his navicular bone in June of 2010 and it cost him the remainder of the season, with the exception of two games when he attempted a comeback.

Indications are that Ross has a less extensive fracture than Pedroia.

Ryan Sweeney also is out of the lineup as the Red Sox wait for the results of a concussion test administered by Major League Baseball. There is a chance he could be available for the game.

Kevin Youkilis is expected to replace Ross on the roster on Tuesday.

Ross will join fellow outfielders Carl Crawford (March 26, left wrist); Ryan Kalish (April 4, left shoulder); Jacoby Ellsbury (April 14, right shoulder); Jason Repko (April 21, left shoulder) and Darnell McDonald (May 12, right oblique) on the disabled list.

UPDATE, 7:00 p.m.: 'The MRI on Cody revealed a small fracture. It didn't show up on the X-rays but was there on MRI," GM Ben Cherington said.

"It's a small, non-displaced fracture so it should heal without surgical intervention. He'll get a second opinion and hopefully came back as soon as possible."

The break is in a slightly different spit than Pedroia had his and is smaller. "Our medical staff is confident surgery won't be necessary," said Cherington, who hopes Ross will be out 6-8 weeks.

"We just have to let him heal and see how he does. Check in two weeks and see where he is then."