The Red Sox will likely wait until Tuesday to officially place Ross on the disabled list. The outfielder was en route to Baltimore from Boston, where he underwent an MRI.
"It's a small fracture, it's non-displaced," said general manager Ben Cherington. "It should heal without any sort of surgical intervention. We just have to let it heal and we'll get him back as soon as we can. It's hard to say [a timetable]. Six to eight weeks is sort of a general framework. We've just got to let him heal and see how he does."
Ross will soon become the sixth Boston outfielder on the DL, joining Jacoby Ellsbury, Carl Crawford, Darnell McDonald, Ryan Kalish and Jason Repko.
Ross suffered the injury while fouling a ball off his left foot in Friday night's 6-4 loss to the Phillies.
Dustin Pedroia fractured his left navicular bone on June 25, 2010, after fouling a ball off his foot in San Francisco. However, Pedroia's injury seemed more severe. He returned to the lineup on Aug. 17 of that season, but only for two days. Pedroia later underwent surgery.
"Same bone, but from what I gathered from our medical staff, it's in a slightly different spot and it's a slightly smaller line, so our medical staff is confident that it will heal without needing surgery," said Cherington. "He'll get a second opinion."
Ross certainly seemed to have enough armor to prevent an injury such as this.
"The amazing thing is he wears a whole catcher's shin guard and it missed it," manager Bobby Valentine said. "It's amazing. He swung and rolled a little over like this, so the ball got underneath the small bone."
It could be the Red Sox are waiting until Tuesday to place Ross on the disabled list because Kevin Youkilis is likely to be activated at that point.
"These things have a way of working themselves out, don't they?" Valentine said.
Ross is hitting .271 with eight homers and 28 RBIs.
Cherington will monitor the trade market in an effort to bolster his outfield depth.
The GM said that Ellsbury, who separated his right shoulder on April 13, could return in early July. Crawford, who first underwent left wrist surgery and then suffered a UCL injury in his left elbow, could also come back some time that month.
In the meantime, the Red Sox will try to get by with what they have.
"We've looked at different things, internally and externally," Cherington said. "We'll continue to do that. We're looking for ways to upgrade. We've been banged up in the outfield before today. We were looking for ways to upgrade if we could; we'll continue to do that, but there's nothing imminent."