How do Victor Martinez and Adrian Gonzalez fit into the Red Sox roster?

Both rumored to be coming to the Sox, i dont see how another 1b and c/1b would work. youkilis and laroache are already there and lowell and youk and gonzalez/martinez won't want to split playing time the whole year and for years to come. At catcher, varitek is not just going to go "away" so how does this work? I've been wondering this everytime i hear these rumors on espn.