The Sean McDermott era’s defensive philosophy is officially being dismantled in Buffalo, and new head coach Joe Brady’s first big move proves it. Hiring former Bills safety Jim Leonhard as the team’s defensive coordinator, it signals a major shift for the franchise, which could move away from schemes used in previous years.

Leonhard noted that while he respects the foundation built before him, his job is to transition the roster to fit his specific vision for a more aggressive team.

“I got a tremendous amount of respect for the coaches that were here,” Sports Anchor Dan Fetes shared on his X account, quoting what Bills defensive coordinator Jim Leonhard said. “We’re going to do it a little bit differently than they did… they built this roster, it’s my job to help flip it & transition it to what my vision is for this team.”

For much of Sean McDermott’s tenure, Buffalo operated out of a 4-3 defense built around four linemen and three linebackers. The system leaned heavily on zone coverage and prioritized disciplined positioning over frequent blitzing. It was a steady, sound approach, though it sometimes struggled to generate the kind of consistent pressure needed to unsettle the league’s top quarterbacks.

Under Leonhard, the Bills could switch to a “3-4” base defense, utilizing three linemen and four linebackers. This setup is much more flexible and allows the defense to attack from different angles. Coach Brady has already hinted that fans should expect to see the team “attack” opposing quarterbacks much more often. This likely means a significant increase in blitzing to keep the offense off-balance.

If history is anything to go by, Leonhard’s unit tended to blitz at a high rate in Denver (20.9 percent, second-highest in the league last year), and they played more man coverage (31.3 percent, fourth-highest). By deploying a 3-4 defense, an off-ball linebacker will move to the line of scrimmage occasionally to show a four-man front and create more chaos.

Depending on who the Bills are facing, Leonhard can move both off-ball linebackers to the line to make a five-man front. In Denver, he saw the Broncos using wide spacing in their defensive system to create quicker paths to the quarterback. Just like McDermott, Leonhard will use disguised coverages and simulated pressures, but the 3-4 change will allow the Bills to show more looks throughout a game.

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“Nowadays, the best defenses and the best minds are continuing all the way through the play call, putting stress on coordinators,” Brady said during his first press conference last Thursday at One Bills Drive.

Leonhard brings a proven track record of being bold. By moving to this hybrid, attacking style, the Bills hope to fix their past struggles against the run and turn their defense into one of the most elite units in the NFL for the 2026 season.

While the defense is undergoing an overhaul, the pressure on the other side of the ball remains squarely on Josh Allen’s shoulders.

Josh Allen focused on Super Bowl goal amid coaching changes

For the first time in his NFL career, quarterback Josh Allen is preparing for a season under a new head coach, and despite the change, his focus remains squarely on the Super Bowl.

“Just give me another opportunity,” he said in an interview with Chris Hassel for CBS Sports. “Let me lead this team and try to get ourselves to the playoffs and get another opportunity in the playoffs—that’s all I can ask for, to be honest.”

The transition comes after a bittersweet finish to the previous season. In a tough loss to Denver, Allen showed why he is one of the league’s most dynamic players by racking up 283 passing yards and three touchdowns, while also leading the team on the ground with 66 rushing yards. However, the performance was marred by two interceptions and three fumbles.

These mistakes proved costly, and many believe that Joe Brady’s offensive expertise might be the key to helping Allen play with more consistent, calculated aggression and better consistency in those high-stakes moments.

Buffalo heads into this new era with a mix of high expectations and immense pressure. The team has made the playoffs for seven consecutive years and reached the AFC Championship twice during that span, yet the Super Bowl has remained out of reach. 

With Joe Brady at the helm and Brandon Beane overseeing operations as the President of Football Operations, the 2026 season is shaping up to be a defining moment for the franchise as they look to finally get over the hump and capture the elusive Super Bowl title.