1. TE Aaron Hernandez - The removal of one of the biggest receiving threats means that the Patriots will be playing with two tight ends: Rob Gronkowski and Alge Crumpler. Only Gronk is a receiving threat. Expect a larger role for Brandon Tate in the offense as Hernandez sits. Also, expect more red zone looks to Gronk.
2. OLB Jermaine Cunningham - The Patriots' best run stuffing OLB is going to be riding the pine, which means the Patriots will be playing with Tully Banta-Cain, Eric Moore and Rob Ninkovich as the OLBs on the roster. Neither Banta-Cain or Ninkovich are as strong at stopping the run and Moore has only been utilized as a defensive end in the 4-3 sub defense. The Patriots might struggle against the run, which is bad news because running back Fred Jackson is an impressive player. The Patriots might use some heavy 4-3 defensive lines, as opposed to their traditional sub defense, in order to slow the run.
3. OG Dan Connolly - The Patriots will be without their starting RG (again) as Connolly sits with a concussion. The Patriots will have to play back-up guard (and the off-season's 5th string guard) Ryan Wendell. Wendell is much smaller than Connolly (6'4, 315 vs 6'2, 290), which means I wouldn't be surprised if the Bills lined Kyle Williams on the opposite side of his traditional position. Wendell will most likely need help, so I would expect the Patriots to line Alge Crumpler on the line for the entire game in order to slide lineman help wherever needed.
4. DE Brandon Deaderick - Deaderick is out, but Ron Brace is not listed as "OUT", which means that Brace might be playing. Deaderick sitting out isn't that big of a deal because he's the 5th lineman on the depth chart (behind Vince Wilfork, Gerard Warren, Ron Brace and Kyle Love), but he definitely affects the depth on the line.
5+6. DL Mike Wright and DL Myron Pryor - Both Wright and Pryor have been sitting out for a while so they won't have a large impact on the Patriots' or the Bills' game plan.