The injury, which occurred when Ross fouled a pitch off the foot Friday night in Philadelphia, was revealed in an MRI taken in Boston on Monday after initial X-rays were negative.
With the loss of the right-handed hitting Ross, Cherington said the Red Sox are discussing keeping rookie third baseman Will Middlebrooks when Kevin Youkilis rejoins the team, which is expected to happen Tuesday. Youkilis was in Norfolk, Va., Monday night, making his fourth rehab start for Triple-A Pawtucket.
"We have talked about it," Cherington said. "We lost a good right-handed hitter today for a while. It's hard to lose more right-handed hitters, so it's a consideration in light of that."
The fracture is in the navicular bone, which is the same bone in which Dustin Pedroia sustained a nondisplaced fracture on June 25, 2010. Pedroia eventually required surgery after an aborted comeback effort and missed a total of 85 games.
Cherington said that the Red Sox medical staff is confident that Ross will be able to avoid surgery, but that the outfielder, who was returning to Baltimore Monday night, was planning to seek a second opinion.
"It's the same bone" as Pedroia's break, Cherington said, "but it's a different (injury) from what I gather from our medical staff. It's in a slightly different spot, a slightly smaller line, so our medical staff is confident it will heal without surgery."
Asked to estimate how long Ross would be out, Cherington said, "It's hard to say, but six to eight weeks is a general framework. Let him heal, see how he does. He'll be checked again in two weeks. We'll see where he is and go from there."
Ross will be placed on the disabled list Tuesday, opening a roster spot for Youkilis, who is scheduled to be evaluated Tuesday before being activated. Ross will become the sixth Red Sox outfielder on the DL, joining Carl Crawford, Jacoby Ellsbury, Darnell McDonald, Ryan Kalish and Jason Repko.
Ross will become the 15th Red Sox player to be placed on the DL this season. Entering Monday night's game, the Sox had lost a combined 438 games to players on the DL.
With Ryan Sweeney also unavailable Monday night while the Red Sox awaited results from an MLB-mandated concussion exam, manager Bobby Valentine's outfield consisted of three players who were not on the Opening Day roster: Daniel Nava, Marlon Byrd and Che-Hsuan Lin.
Cherington said that both Ellsbury (partially dislocated shoulder) and Crawford (wrist surgery, sprained elbow) are progressing well in their rehabs, but mentioned early July as a rough timetable for Ellsbury to return, with "early to mid-July" for Crawford. Neither player has begun baseball-specific activity.
Valentine said he elected to keep Sweeney out Monday night after trainers told him the outfielder felt some fatigue after taking swings in the batting cage. Sweeney was diagnosed with what he called a mild concussion after making a diving catch Saturday night in Philadelphia. Afterward, he said he experienced a whiplash-like jolt to his neck.
Valentine said after the game that Sweeney did not pass the concussion tests administered Monday, and said that there was a chance he would have to go on the seven-day disabled list MLB has created for players with concussions.
"I don't know how bad it is,'' Sweeney said after the game. "I did some of the tests on the computer and did OK on the reaction stuff, but I guess they said when you have something like this and you over-exert yourself and try to do too much, you've got to let your head heal.
"I did some hitting and some bike, and just felt a little tired. I have to come in tomorrow and see how I feel.''
"It feels like a lot of guys are banged up at once," Cherington said. "Our options are to keep playing. Our guys in the lineup are our guys in the lineup tonight. We've got to keep looking for reinforcements. We'll likely have a move, if not more, for tomorrow. We've got to keep looking, but guys have already persevered through some tough times and played through injuries. We've got to keep playing and hang in tough."
Ross was batting .271 with eight home runs, second on the team to David Ortiz's 10, and his 28 RBIs also ranked second to Ortiz's 30. Friday night against the Phillies, Ross doubled and homered before fouling a pitch off the foot during his eighth-inning at-bat, which ended with a strikeout.
He was struck by the foul ball even though he wears a shin guard that covers the top of his foot. The foul ball struck him at the top of his instep, according to Valentine.
Scouts from the Cincinnati Reds, Philadelphia Phillies and Atlanta Braves were all in Norfolk on Saturday night to watch Youkilis play, and were expected to be in attendance Monday. Youkilis was 3 for 9 with a double in Pawtucket entering Monday night.
Rookie Middlebrooks, meanwhile, has hit safely in 14 of 18 games since his call-up on May 2, entering Monday night's game with a .275 average, five home runs, 15 RBIs and .886 OPS. Valentine has entrusted him with the fifth spot in the batting order, where he has been batting behind Adrian Gonzalez and Ortiz. He also has shown outstanding skills at third base.
Even before Ross' injury, the decision on what to do with Middlebrooks upon Youkilis' return was not an easy one. Without Ross, it seems a virtual certainty that the Sox will keep Middlebrooks, although Cherington said no final decision has been made.
"We're still talking about it to make sure we see how it would work," he said. "At a time like this, it's important to kind of slow things down and try to make decisions for the right reasons. We want to do what's best for the team, but also best for the players. It is something we discussed. We've talked about what it would look like if we did.
"At a time when you have a lot of injuries in one spot, sometimes you've got to come up with solutions you might not have thought of two months ago. We're talking about all sorts of things."
One scenario under consideration is playing Gonzalez in right field, which would free up first base for Youkilis while keeping Middlebrooks at third. Gonzalez, who has played the outfield in winter league ball and made a good accounting of himself in right field in weekend games in Philly, said he is comfortable in the outfield and willing to play there. His lack of speed, however, would make that problematic in a large right field, like the one in Fenway.
"If Ben and I decided that was something we should pursue I think there is a way of trying to make it work,'' Valentine said of retaining Middlebrooks.
"It's all a balancing thing. What's right for (Middlebrooks), what's right for us, what's right for Youk, what's right for the rest of the guys. It's a tough situation, a lot of these things have a way of working their way out."
Valentine said that playing third base is more demanding than first base, especially for a player as oft-injured as Youkilis.
"That would be up to Youk," he said when asked how much he thinks Youkilis can play. "If he says he's comfortable, I'd be comfortable. There's no way I can put a number of ground balls, at-bats, innings. I have no idea."