5. Mike Mularkey (2004-2005)
Record: 14-18
After Gregg Williams, the Buffalo Bills tried to find a coach who could help the offense and elected to hire Mike Mularkey, who spent a number of years with the Pittsburgh Steelers as tight end coach and offensive coordinator.
Mularkey's best season in Buffalo was his first as the Bills would go 9-6 over the first 15 games and entered the regular season finale that had them in a position to end their playoff drought. However, the Steelers with most of their backups on the field, like quarterback Tommy Maddox, were able to come away with a win in Buffalo and the Bills would see their season come to an end.
Mike Mularkey's time in Buffalo wouldn't get any better as the Bills would go 5-11 in what would be his final season in Buffalo. The reason was that he unexpectedly resign after the season, due in part to concerns about the direction the franchise was heading. If he remained with the franchise, he likely would be higher on these rankings.