Eh, I'm a bit skeptical. He's already 30, which means the last half of the deal will likely be a big pill for the Sox to swallow, and he's struggled in the postseason (though the sample size is a little on the small side).
He's definitely the regular-season ace the team needs. Here's to hoping they also sign a level-1B guy as well (Zimmerman type), in case one (or more) of E-Rod, Owens, Porcello, Kelly, and Miley conks out.