The deal was reached shortly after the Bills interviewed McDermott for a second time in eight days. The 42-year-old has no previous head-coaching experience and spent the last six seasons working as the
McDermott has 18 seasons of NFL experience, spending his first 12 years with the Philadelphia Eagles. He started as a scouting coordinator for two years, then mentored under late defensive coordinator Jim Johnson. He eventually succeeded Johnson in 2009.
He takes over a team in Buffalo that featured the NFL's top running attack but an underperforming defense in two seasons under Ryan.
The Bills defense finished 19th in yards allowed two years straight, and was particularly porous against the run. Buffalo allowed 200-plus yards rushing to opposing running backs three times this season, including twice against Miami's Jay Ajayi.
The offense was inconsistent at times under second-year starter Tyrod Taylor.
Owner Terry Pegula grew so dissatisfied with the defensive meltdowns, he fired Ryan in the week leading up to Buffalo's final game. Ryan was replaced by offensive coordinator Anthony Lynn, who served as interim coach in a season-ending loss to the