There’s a defensive revival going on in long-dormant Buffalo. And right smack dab in the middle of it is former Vikings head coach Leslie Frazier.

When the Bills gave Sean McDermott his first head coaching job last spring, he asked Frazier to be his defensive coordinator. The two had worked together in Philadelphia under Andy Reid from 1999 to 2002, when Frazier left to become Cincinnati’s defensive coordinator.

Frazier, 58, was Reid’s defensive backs coach. McDermott, who’s 15 years younger, was a scouting assistant and then a defensive quality control assistant.

Frazier was Baltimore’s defensive backs coach when McDermott reached out to him last spring. McDermott had spent the previous six seasons as Carolina’s defensive coordinator but told Frazier he wanted him to make the defensive calls on game days.

Then McDermott put that on record, handing over the play-calling duties while expressing the utmost confidence in Frazier’s abilities.

“And Sean has been true to his word,” Frazier said this week. “He has been great. Of course, it helps that we both learned defense from one of the all-time greats in Jim Johnson in Philadelphia.”

The Vikings fired Frazier after the 2013 season. By then, his defense had dropped to last in the league in points allowed (30.0).

But people forget that Frazier’s defenses also ranked in the top eight in yards allowed three times when he was Vikings defensive coordinator. They also led the league in run defense twice.

Through a quarter of this NFL season, the two biggest surprises are the offensively supercharged Rams (3-1) and the stingy Bills (3-1). The Bills lead the league in fewest points allowed (13.5). The closest challenger is Pittsburgh at 14.8.

Frazier still plays a lot of Cover 2, but he and McDermott have put their heads together to create a more aggressive version of what Frazier employed toward the end in Minnesota.

A good example came early on in Sunday’s upset victory in Atlanta. The Falcons are one of the toughest teams in the league to stop on the opening drives of games, and a lot of other times as well.

Matt Ryan faced third-and-6 near midfield when he dropped back. Frazier sent seven defenders after him. Seven.

Ryan barely avoided the sack with a “throw” that had to be reviewed to make sure it wasn’t a strip-sack fumble.

The Bills were a 3-4 team under Rex Ryan. Now, they run a 4-3.

That has made for some uncomfortable changes defensively. None more so than what has happened to defensive tackle Marcell Dareus.

In 2015, Dareus became the highest-paid player on the team and one of the highest-paid in the league. He was the perfect 3-4 lineman, so the Bills handed him a six-year, $95 million deal with $60 million in guarantees.

His salary cap number is $16.1 million. But he no longer fits Buffalo’s defense, so he played only 22 snaps last week, the fewest among Buffalo’s defensive players.

Meanwhile, the entire starting secondary is new this year. At safety, Micah Hyde was brought in from Green Bay and Jordan Poyer from Cleveland. At cornerback, Tre’Davious White was drafted in the first round, while E.J. Gaines arrived as part of the Sammy Watkins trade with the Rams.

The linebackers are smaller and more active. The leading tackler is nine-year veteran Ramon Humber, the Minneapolis native who played collegiately at North Dakota State.

Mix it all together and it’s working. The Bills haven’t allowed an opponent to score more than 17 points. They’ve given up one touchdown pass, intercepted six passes and have a defensive passer rating of 64.1.

Keep it up and, who knows, maybe the Bills can make the playoffs for the first time since the 1999 season. With a half-game lead over New England, this is the latest they’ve led the AFC East since 2008.

“The defense this year is a lot simpler,” middle linebacker Preston Brown said. “Guys are having fun, running around and just playing fast.”

 

Mark Craig is an NFL and Vikings Insider. Twitter: @markcraigNFL

E-mail: mcraig@startribune.com