There is little doubt Miami will be playing to win. Even a seed jump as semi-inconsequential as #6 to #5, it is something quite tangible to play for. Further, the Phins would love to roll into the Playoffs having planted their flag in the ground with a triumph in Foxboro against the Patriots.
With that said, if the Patriot O and D pitch a strong first half, I think there will end up being room in the 4th quarter for resting anyone in extra need of it. I suspect a strong first half may cause some Miami players to be thinking of the flight home and balmy temps of Florida as a much better place to be mentally instead of concentrating on the icy battering of a second half game they appear to have no chance of winning.