Okay, if we take last year, and the Bills have an average QB, let's say, a decent starter (not Mahomes but maybe something better than Trubisky) I'd say it would have gone as follows:
Arizona W
at Miami W
Jacksonville W
at Baltimore L
at Houston L
at NY Jets L
Tennessee W
at Seattle W
Miami L
at Indianapolis L
Kansas City L
San Francisco W
at LA Rams L
at Detroit L
New England W
NY Jets W
at New England W (in this scenario, the starters would have played in this game)
So, 9-8, maybe a playoff team