What We Learned at Bills Training Camp: It’s Jim Leonhard’s Defensive Scheme or Bust

ROCHESTER, N.Y.—Sean McDermott wasn’t at Bills training camp on Friday. And it’s not because of Buffalo’s offense.

After nine years as coach, McDermott was let go after a crushing 33–30 overtime loss to the Broncos in the divisional playoffs. Once again, the defense couldn’t get a stop when needed, marking the sixth time in seven playoff losses under McDermott that Buffalo permitted at least 27 points, allowing an average of 33.1 points in those defeats.

With McDermott gone and Joe Brady promoted from offensive coordinator, the Bills are hoping to see the offense maintain its level (top six in each season since 2020) while adding an explosive element in wideout DJ Moore. But more importantly, Buffalo fans are looking for new defensive coordinator Jim Leonhard to create better results in big moments.

Leonard, who comes over from Denver and its second-ranked defense, has the Bills transitioning from a 4–3 to a 3–4 scheme. The change has created a deluge of substitutions and rotations in the front seven, with Leonhard and his staff trying to decipher the right fits with five weeks to go before a Week 1 matchup against the Texans.

“For me, personally, I’ve done it one way for a long time,” veteran inside linebacker Terrel Bernard said. “So trying to flip my mind and work that system, I think that’s the biggest thing. Just knowing how all the parts are moving and who you’re working with. In the run game, just who’s in the fit. Besides that, I feel like we’ve grown a lot and gotten the details down to a level that we’ve come out here and executed pretty well.”

For Leonhard, the challenge isn’t having a top-ranked defense. Buffalo has seen those before with McDermott, and watched as the paper tiger fell apart in the postseason. During McDermott’s tenure, Buffalo ranked top 10 in yards six times, including being No. 1 twice.

Yet, the biggest issue among those units was often the lack of game-changing plays. In McDermott’s six playoff losses in either the divisional or AFC title games, the Bills had only six total sacks and three defensive takeaways. The result was not creating enough negative plays for superstar quarterbacks Patrick Mahomes and Joe Burrow, who were responsible for five of those losses.

During team periods throughout Friday’s practice, the final one at St. John Fisher University before the team returns to its new digs in Buffalo, the Bills are still sorting through a variety of potential answers.

While the front seven is going to be anchored by nose tackle Deone Walker, defensive end Ed Oliver, and the edge rush duo of Bradley Chubb and Gregory Rousseau, everything else is fluid. Buffalo rotated different players into the front, including second-year players TJ Sanders and Landon Jackson, rookie second-round edge T.J. Parker and linebacker Andre Jones Jr. That’s to say nothing of rookie linebacker Kaleb Elarms-Orr, who has been a camp standout and could earn the starting nod next to Bernard.

With so many moving parts, the Bills will be challenged early to perform at their peak. Buffalo’s first five games against four 2025 playoff teams—Texans, Chargers, Patriots and Rams—will only complicate matters, with a Week 2 home opener against the Lions. In that regard, the preseason will be crucial, as many players attempt to earn snaps, while some are looking to process the scheme change in real time.

“It’s been good. We’ve got some new teammates, some really good football players in the building,” Bernard says. “Seeing all those guys mesh and gel together has been fun. I’m excited to see where we go.”

In the secondary, there will also be change. With new defensive backs coach Jay Valai, Buffalo is working in slot corner Dee Alford and safety C.J. Gardner-Johnson while becoming a group that will rely more on match coverage, a staple Leonhard helped coach with the Broncos. Buffalo was predominantly a zone team under McDermott.

“The biggest adjustment is probably a different technique,” cornerback Christian Benford said. “Understanding how and when to apply those techniques.”

While the defensive backfield will be the group least impacted by the scheme change, it’s still a new world for Benford, who is joined at corner by rookie second-round pick Davison Igbinosun, second-year man Maxwell Hairston and Alford. Chemistry will be at a premium with Jared Goff, Justin Herbert, Drake Maye and Matthew Stafford on the schedule before Halloween.

For the firing of McDermott to prove correct, his old unit must finally make the stops it never did with him on the sideline.

Buffalo Bills quarterback Josh Allen — Bills quarterback Josh Allen signs autographs at training camp. | USA TODAY Network via Reuters Connect

Legends show up at practice

Walk around for a few minutes at camp, and you’ll see someone beloved by Bills fans.

Standing on the sideline, the first roar from the crowd could be heard when Josh Allen came off a side field and onto the main one. Waving his arms to motivate the fans, his followers delivered. At that moment, former Bills and Hall of Fame quarterback Jim Kelly walked by and joked he thought the ovation was for him.

Of course, Kelly got many of those over the years, having led Buffalo to four consecutive Super Bowls in the 1990s. Then, there was special teams ace Steve Tasker, who spent 12 years with the Bills (1986 to ’97), including all of those Super Bowl runs. Now part of the team’s media arm, Tasker watched much of the practice while former center Mitch Morse did the same, having hiked the ball to Allen for five seasons.

While every fanbase loves its best players (especially the quarterbacks), there’s a special love for Allen. Buffalo is a small-market club without a big-league championship. The Bills and Sabres have come close. The Braves relocated long ago to become the NBA’s Clippers. It’s a passionate group of fans that has endured bad weather and even worse jokes at its expense. Allen is their hero, the guy making good for them.

When Allen was soaking in the cheers, he had to be feeling great. And while Kelly made his joke, he also had to be remembering the good times despite lacking that final line on his resumè—a line Allen hopes to fill in on his come February.

Add us as a preferred source on Google