Jim Leonhard Exposes Two Sean McDermott Shortcomings That Cost Bills' Defense Dearly

Although he didn't know not at the time, Buffalo Bills' first-year defensive coordinator Jim Leonhard was a firsthand witness to Sean McDermott's final playoff stinker.

Heading into the 2025 AFC Divisional Round road contest against the Denver Broncos, the Bills' defense had allowed 33.2 points per game over its last five playoff losses (2020-24).

Rather predictably, even with inexperienced quarterback Bo Nix leading the way, the Broncos put up 33 points on the McDermott-influenced unit this past January. The Bills' defense did not record a sack and registered only one takeaway in the overtime loss.

Josh Allen tackled — Jan 17, 2026; Denver, CO, USA; Denver Broncos defensive tackle Malcolm Roach (97) tackles Buffalo Bills quarterback Josh Allen (17) during the second quarter of an AFC Divisional Round playoff game | IMAGN IMAGES via Reuters Connect

Meanwhile, the Broncos' defense, with Leonhard as the pass game coordinator, sacked Josh Allen three times and came away with five turnovers.

Only months later, Leonhard, a former 10-year NFL safety, leads the Bills' defensive overhaul in the wake of McDermott's dismissal. Ahead of the August 15 preseason opener, Leonhard highlighted the two major areas where Buffalo must begin to improve.

Bills new defensive coordinator Jim Leonhard during the opening day of Buffalo Bills training camp at St. John Fisher University Wednesday, July 29, 2026 in Pittsford. | USA TODAY Network via Reuters Connect

Poor tackling proves costly

With the preseason opener being the first chance for Leonhard to evaluate his personnel during live game action, the former 10-year NFL safety is placing a heavy focus on tackling.

"It's the first opportunity to finish. Tackling, right? Tackling, tackling, getting guys on the ground in live situations, making plays on the ball. You go through an entire training camp, the quarterback doesn't get hit," said Leonhard.

The Bills struggled mightily against the run under McDermott in 2025 due in large part to poor tackling. With an inability to consistently get the ball carrier to the ground, Buffalo allowed 5.14 yards per run play, ranking 30th on the circuit.

"Who can finish, get guys on the ground? That's was an Achilles heel here last year, so that's the number one thing we have to to correct, and the number one way to do it is getting population to the football," said Leonhard.

McDermott's punchless pass rush

The Bills seemingly struggled to pressure the passer in key spots throughout McDermott's tenure. They totaled one sack combined over two playoffs games last season.

Buffalo's former head coach was insistent on generating a pass rush by using only the front four, rarely dropping any fewer than seven men in coverage. Even when blitzing, the Bills were unable to get home the majority of the time.

Jan 17, 2026; Denver, CO, USA; Buffalo Bills head coach Sean McDermott during the second quarter of an AFC Divisional Round playoff game against the Denver Broncos | IMAGN IMAGES via Reuters Connect

"You can't pressure just to pressure. You can't do it recklessly. I've mentioned that multiple times," said Leonhard. "If you don't get home, the coverage is stressed. It's just what it is, so there's always a balance."

With Leonhard on board, the Broncos found that balance in 2025, leading the NFL by making 68 sacks.

"You have to understand the DNA of your team. Some guys can be aggressive and overaggressive because that fits who they've got in the building and others are a little bit different. That's what I have to find out. I'm getting a better sense of it as these practices go on of what we can and can't do," said Leonhard.

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