The Buffalo Bills made major changes on the defensive side of the ball that should better equip players to learn and play under first-year defensive coordinator Jim Leonhard. They will be switching from a 4-2-5 approach to an aggressive multiple 3-4 scheme that should better fit some of the current players' strengths.
Instead of going all in to keep adding defensive line pieces while keeping the 4-2-5 scheme, the Bills will implement a new scheme that offers versatility and aggression to pressure the quarterback. The Bills will try to create pressure from all angles on the defensive unit in an attempt to force more teams into longer second or third downs, setting up a 5-man pass rush on the money downs.
Let's take a look at how the Bills' 2026 roster compares to that of 2025.
Bills' defensive additions in 2026 vs. 2025
Defensive line must show improvement from 2025
Last season, the Bills made a huge commitment to start building a younger, faster defense by investing their draft capital in collegiate defensive line stars. It was a 50-50 result: Deone Walker exceeded expectations in his rookie year and will look to take a step forward in Year 2 with a different defensive scheme.
Unfortunately, T.J. Sanders did not produce immediate results as a second-round draft pick due to early-season injuries and adapting to the scheme later in the season. With his physical attributes and strength, the new scheme will allow Sanders to flourish more as a 1-tech or 5-tech power-rushing defensive end at 6-foot-4, 297 pounds.
While there is unproven talent at linebacker and in the secondary, the depth of the D-line includes 2026 fifth-round pick Zane Durant out of Penn State, nose tackle DeWayne Carter out of Duke, Phidarian Mathis, Zion Louge, and Tommy Akingbesote.
Just because the talent might be unproven, it also may have been misused in the 4-2-5 scheme under former head coach Sean McDermott. That's why Leonhard is confident that his scheme might be a better fit with the current personnel this year.
There may be one bright spot the Bills added from 2025, and he is edge rusher Landon Jackson. The third-round draft pick out of Arkansas will move from a 4-2-5 edge rusher to a 4i tech 3-4 defensive tackle, which might allow him to use his power even more to attack the quarterback from a side angle, from where the center is.
Pass rush has to step forward
General manager Brandon Beane brought in his bread-and-butter power-edge rushers by adding Bradley Chubb from the Miami Dolphins and drafting T.J. Parker out of Clemson in the second round of the 2026 NFL Draft.
Both of their hard-nosed styles of play and getting to the quarterback, should help assist Greg Rousseau as he looks to improve on the 8.5 sacks he compiled in 2025.
Lack of depth at linebacker position
The Bills' linebacker depth might not be as strong as it was last year. But the players they do have all fit this scheme well. Gone is longtime linebacker Matt Milano, who had a huge cap hit at 32 years old and never played in a 3-4 defense before.
While Terrel Bernard struggled last season, he has shown he can play in a 3-3-5 defense in college as well as a 4-2-5 in the NFL, as does Dorian Williams when healthy.
The biggest addition the Bills made at linebacker was drafting the big-thumping linebacker out of TCU, Kaleb Elarms-Orr, who might start Week 1 for the Bills.
The Bills definitely have the starting talent necessary to run this 3-4 defense. But they may have to re-sign Shaq Thompson or rely on former undrafted free agent Joe Andreessen to earn more playing time in 2026.
Very little depth at cornerback
Second-round pick Davison Igbinosun might be the most pro-ready cornerback this Bills team has as a rookie. He has the tools at 6 foot-2, 193 pounds, with the size and the man-man cover skills to be able to shut down some of the NFL's most powerful and talented wide receivers today.
As for Maxwell Hairston, he's a smaller but faster corner at 5-foot 11, 192 pounds, with above-average man-coverage skills and exceptional zone-cover skills. After missing some of 2025 with injuries, let's hope he can light it up this season.
Also returning is Christian Benford, who is already showing to be one of the league's premier lockdown corners in the game. The new scheme may allow him to sack the quarterback on those deep corner blitzes and also force more interceptions with an instant read on the ball.
The other cornerbacks will have to fight it out for a nickel role, and while this room is talented, they will always have fan favorite Tre'Davious White out there as an option to potentially bring back.
Bills made some noise at safety position
Every successful team in the NFL has that one character on their team who is irritating to play against, but you love him when he's on your team. C.J. Gardner-Johnson is that player for the Bills, and he isn't afraid to speak his mind and try to stir up the locker room with some motivation and drama.
The Bills really didn't have that type of player the last nine years under McDermott, and Brady decided to try a different path in Year 1 of his tenure.
They also added Geno Stone, who's another talker, but is a guy that will show up and make the tough plays, especially come playoff time. Pairing him with Gardner-Johnson could be another Batman and Robin tag team at that position.
Overall, look for the defense to be young, fast, and aggressive and to take tremendous steps forward from 2025 to 2026, as the goal for this unit is to attack the ball from all sides of the field and create chaos on opposing quarterbacks.
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