If Buffalo wins out, they will beat the Patriots once in the process, evening the teams’ records. The Bills would still lose the tiebreaker to New England, so the Patriots would still need to lose another game either to the Cincinnati Bengals in Week 15 or the Miami Dolphins in Week 17.
If the Bills lose to the Pittsburgh Steelers in Week 15, the Bills can still win the division if the Patriots lose to the Dolphins in Week 17 and Buffalo wins in Weeks 16 (Patriots) and 17 (New York Jets).
The Bills can’t be eliminated from the AFC East race before Week 16, so that game is going to have implications one way or the other when Buffalo travels to Massachusetts.
So, put simply, the AFC East crown comes back to Orchard Park if:
Buffalo Bills win out AND New England Patriots lose one of their other two games
* or *
Buffalo beats the Patriots and Jets AND the Patriots lose to Miami Dolphins