FTW: Sean McDermott exactly what Bills needed

Sean McDermott wasn't the biggest coaching name available this offseason, but for the Buffalo Bills, he was the perfect choice for a franchise that did not come anywhere close to playing up to its potential under Rex Ryan.

McDermott spent six seasons in Carolina working under Ron Rivera, and he can best be described as a problem-solver. Whatever issues the Panthers defense had at the beginning of a season, they were solved by the end of it. That's a big reason why Carolina sits behind only New England and Green Bay in December winning percentage since 2011, per Pro-Football-Reference.com.

The Panthers' defensive scheme was not overly complicated at the beginning of McDermott's tenure. Out of necessity, the Panthers ran conservative zone coverages behind a four-man rush. The secondary was among the worst in the league and the team had a strong defensive line.

As Luke Kuechly and Thomas Davis emerged as the best linebacker pair in the league, the defensive identity began to shift. Carolina was still playing those basic zone defenses, but with two smart, ball-hawking linebackers, they could mix things up a little more. We started seeing more creative blitzes on third down, which helped make up for the loss of end Greg Hardy and the regression of the aging Charles Johnson.