The Pats might not cut players with big money guaranteed, but:
1. The Pats have a much better free agent track record than the Red Sox. I really don't see any Pats free agent busts. They go after good players who are undevalued. The Red Sox say they look for value, but it really hasn't translated well in their free agent signings. Each many of the signings, they paid alot more than the next team was offering, and many of them have played horribly here(Drew, Crisp, Rentaria, etc).
2. The Pats would sit the guy with the big contract if the guy (Bledsoe/Brady prime example, benching Terry Glenn for most of the season, Gabriel last year) if either the big contract guy had an effort/attitude problem, or if the little guy was simply better. The Sox, would be afraid to hurt the big contract's ego, and wouldn't make a move. And in the regular season, it doesn't matter too much, since the Sox have so many stars (due to payroll advantage) that you can afford to carry some deadweight. In the playoffs, as we're now witnessing, it does matter when you don't make the best coaching moves.