Williams was known as a gifted defensive coach while Mularkey is considered a guru in training on the offensive side of the ball.
In that respect, the Mularkey move made sense. The Bills' offense was atrocious last season and their defense was among the league's best. But it will be difficult for fans in western New York to get excited about the former Pittsburgh Steelers offensive coordinator. That's not because he has no prior head coaching experience, but because his recent history of calling plays will be hard to swallow.