The Bills were always going to look different on defense in 2026.
From the time the firing of former head coach Sean McDermott was announced in the early parts of 2026, we all knew that Buffalo Bills owner Terry Pegula was pointing to coaching for a reason, and it wasn’t the performance of the team’s offense. So when new head coach and former offensive coordinator Joe Brady hired Jim Leonhard to be his defensive coordinator, everyone knew that qualitatively, what the Bills looked like on defense in 2026 would
be very different than what the fans had been used to seeing from that unit for the previous nine years.
Through six weeks of the 2026 regular season, the Bills defense has absolutely looked different than it has in previous years. It’s also objectively been worse (data from Fantasy Points Data Suite).
The Buffalo defense thus far in 2026 is:
30th in EPA per play allowed
28th in EPA per drop back
25th in EPA per rush
28th in success rate against
28th in explosive play rate against
To put this in perspective, in 2025 in the same categories, the Bills were:
14th in EPA per play allowed
8th in EPA per drop back
31st in EPA per rush
11th in success rate against
25th in explosive play rate against
When your eyes tell you that the team has been a little better against the run than in 2025, your eyes are right. Everything else in terms of resultant defensive metrics is not just worse, but bad.
How did we get here? What’s different stylistically in 2026 versus previous years? The biggest and most glaring departure for the 2026 is that the Bills, for a decade one of the most nickel-stubborn teams in the National Football League, are now running base personnel 36.2% of their defensive snaps (9th in the NFL), up from single digit base defense percentages in most years of the Sean McDermott era. The increased base defensive percentage also leads to the Bills having an average box count of 7.13 (5th in the NFL), compared to 6.87 in 2025 (19th in the league) and 6.52 in 2024 (27th in the league). This heavier phenomenon is a contributing factor to the slightly increased effectiveness against the run, but it’s also a factor in the decreased effectiveness against the pass. the McDermott Bills were well-noted to be a team that refused to be dictated to in terms of defensive personnel, and former nickel defender Taron Johnson was the centerpiece of that philosophy that has changed under Jim Leonhard.
The next defensive characteristic that has changed significantly in 2026 on defense is the Bills coverage splits on defense. We live in a cover 3 league meta right now (current league average for cover 3 usage is 32.7%, the largest plurality of all coverage groups), but the Bills play cover 4 an astounding 26% of the time in 2026 (#1 in the league) while also being above league average in cover 3 usage (34.4% for Buffalo), which means over 60% of the time, the Bills are running either cover 3 or cover 4. Compare this to 2025, when the Bills ran cover 3 at a mark below the league average with cover 4 right at the league average and cover 2 and cover 1 above the league average. This shows that coverage diversity was far more present in 2025 versus 2026.
So the Bills are running a lot more base defense with heavier boxes and a lot more cover 3 and cover 4 (the most cover 4 in the league, even). You may think this is a more aggressive lean, but the Bills are pressing at least one receiver less in 2026 (14.1%, 28th in the league) than the “maligned for ‘soft coverage’” Sean McDermott’s defense in 2025 (30.2%, 7th in the NFL). “Maybe they’re blitzing more”, you say. I mean, a little bit. Buffalo is 20th in the NFL in blitz rate in 2026 (27.9%) and was 23rd in 2025 (24.3%), so not a statistically significantly difference.
If you have a team that is:
- running heavier defensive personnel
- running heavier boxes
- running the most cover 4 in the league
- running a less diverse selection of coverages
- pressing a lot less
- still not blitzing much
You have the 2026 Bills defense compared to the previous and most recent versions of it. And the results make sense: they’ve seen a slight uptick in run defense due to heavier boxes and heavier personnel, but they’re running a lot of cover 4 to prevent explosives, which might get them there if the communication in the back seven wasn’t leading to blown coverages, allowing explosive plays in the pass game despite the cover 4 calls. They’re not blitzing, they’re not pressing, they’re not diversifying, and they’re not disguising (26.3% disguise rate, 28th in the NFL), so quarterbacks aren’t holding the ball (2.68 average time to throw against, 11th in the NFL). Being able to stop the run from two high is the holy grail of NFL defenses (the Bills are top 12 in both two-high and base personnel usage), so you can see the outcome the Bills are trying to generate, but it’s not happening for them through six weeks.
The Bills were trying to get over the hump when they fired Sean McDermott, and they elected to hire a rookie head coach and a rookie defensive coordinator. You can’t do that and then logically not provide any grace for rookie mistakes from your rookie coaches, but the Bills are fortunate to be 5-1 going into their bye week with the defensive generating results this poor. Let’s hope we come out of the bye with a clear identity of how Jim Leonhard and the defense will get where we all want them to go.
…and that’s the way the cookie crumbles. I’m Bruce Nolan with Buffalo Rumblings. You can find me on Twitter and Instagram @BruceExclusive and look for new episodes of “The Bruce Exclusive” every Thursday on the Rumblings Cast Network — see more in my LinkTree!
