Going into the 2026 season, the Buffalo Bills made a major change by bringing in Jim Leonhard as their defensive coordinator. Instead of Sean McDermott's long-running zone-heavy approach, Leonhard is installing an aggressive 3-4 base hybrid built around pressure, movement, and physical play.
So far, one NFL executive already sees the difference.
On Sept. 3, The Athletic's Mike Sando shared a report on how six NFL executives view the AFC. While discussing the conference's top contenders, one executive admitted the Bills made the decision difficult.
"My hardest choice was Houston-Buffalo (for the top spot)," the executive said. "The defensive change (under new coordinator Jim Leonhard) helps; they're a little more violent defensively, a little more athletic defensively. And then it's a top-flight offensive line, and then DJ Moore is going to make an impact."
The defense also gave fans an early reason for optimism during the preseason. Buffalo opened against the Carolina Panthers and put together a solid defensive showing. They carried that momentum into a dominant defensive showing against Cleveland (a 31-7 win) before a shootout win over Pittsburgh in the preseason finale.
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Although preseason results rarely tell the full story, the early performances offer a glimpse of what Leonhard wants from the unit.
Buffalo's defensive transformation carries plenty of context because of how McDermott's tenure ended.
The Bills fired him less than 48 hours after their 33-30 overtime loss to the Denver Broncos in the AFC Divisional Round. Ironically, McDermott built his reputation as a defensive architect before defensive breakdowns hurt Buffalo in crucial playoff moments.
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Before his firing, Buffalo had blown a fourth-quarter lead in four of its last five postseason eliminations under McDermott.
The pattern became especially painful in January 2022, when the Kansas City Chiefs gained 44 yards in 13 seconds and forced overtime. The Chiefs eventually won, adding another difficult chapter to Buffalo's playoff story.
Moreover, the defense showed troubling signs again in 2025. Buffalo allowed at least 24 points in eight games, including the postseason. Those results offered a clear sign that the unit had moved away from the standard McDermott established earlier in his tenure.
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According to PFN's Defense Impact Metric , the Bills posted an impact score of 72.8 last season, ranking 19th in the league.
Still, McDermott deserves plenty of credit for changing the franchise's direction. When he arrived, Buffalo had not reached the playoffs since 1999. He guided the Bills to the postseason in eight of nine years while building a culture centered on accountability.
However, those achievements could not erase the biggest disappointment. Buffalo never reached the Super Bowl under his watch.
Now, Leonhard gets the opportunity to write a different chapter. During training camp and the preseason, he rotated players heavily and gave numerous first-team reps to evaluate his depth.
As a result, Buffalo could enter the season with better combinations and a more aggressive identity. For Bills fans, that fresh approach offers plenty of reason for optimism.
This article originally appeared on Pro Football Network .
