I can understand playing Seattle as a value play, but the odds of them actually winning are very slim IMO. I think the big line is a reflection of the fact that Boston is trying to avoid the sweep. Considering Boston lost the first two games (and didn't even show up for yesterday's game), I doubt this one will be close. I'm guessing either Lester pitches a gem, or Morrow gets shelled, or possibly both.
Seattle's already 5-3 on their road trip, so even if they lose today they will still have a winning trip against the Dodgers, Yankees, and Sox. They said before they left for the trip they just wanted to be over .500. I think you will see a good effort from the Sox and a shitty effort from the M's today. Like I said though, I can understand seeing value in the M's since the line is so high.