V-Mart and Tek should be able to rotate like they are this season. Tek, Papi, and Lowell all need time off. And fortunately for the Sox, V-Mart can fill in for all 3 in one way or another with few to no downgrades at the give position(Youk obviously playing 3B, not V-Mart).
The Sox should sign him to a 4 year deal with a 5 year option. They can always move him to 1B/DH permanently down the road if they decide to pursue another everyday Catcher, like Joe Mauer.