Overview of the Buffalo Bills Defense
Where the 2025 Bills were strong, they were very strong. Where they were weak, they were very weak. The pass defense was outstanding, allowing the fewest yards through the air, the 4th-best completion percentage, the 4th-fewest plays of 20+ yards, and only one pass of 40+. The run defense was the polar opposite. Buffalo was 28th in rushing yards, 30th at 5.1 per carry, and no one gave up more than their 7 long runs of 40+. The pass rush was below average with 36 sacks, and they tied for 15th with 20 turnovers, but managed to end up at 12th in scoring.
Throw out all of last year's numbers. Buffalo moved on from head coach Sean McDermott after the season, hiring Joe Brady to replace him. Defensive coordinator Bobby Babich didn't wait around to see if he would have a job. He packed up and went to Green Bay, so the Bills hired Jim Leonhard away from the Broncos. Leonhard brings a complete, ground-up overhaul that includes the switch from a 4-3 to a base 3-4. Having run a 4-3 for many years, the personnel overhaul started immediately.
The team picked up Bradley Chubb to start on the edge. Then they used their highest draft pick on edge TJ Parker in the second round. Buffalo hit free agency for corner Dee Alford, safety Geno Stone, and slot corner C.J. Gardner-Johnson, adding corner Davison Igbinosun with their other second-round pick, and inside linebacker Kaleb Elarms-Orr in the fourth.
The roster had a good number of guys who could successfully make the switch. Leonhard will strive to make the best of the talent at hand and put a good team on the field this year, while evaluating the holdovers for their long-term fit. We might see significant turnover next offseason, but expect this unit to play fairly well considering the situation in 2025.
Buffalo Bills Defensive Line
The toughest transition between the schemes comes at the edge positions. In a 4-3, the edge guys are generally a little bigger and more contact-oriented. They line up a little tighter, put their hands down, and everything is full speed ahead. In a 3-4, the outside guys are generally a bit smaller and faster. They work from a two-point stance, line up wider, use their speed and agility to avoid contact as much as possible, and sometimes have coverage responsibilities that 4-3 guys rarely see.
Bradley Chubb is a career 3-4 guy and a great addition for the team. As a fantasy prospect, his career has been up and down largely due to injuries. Chubb turned in 42 tackles, 16 assists, 12 sacks, and 3 turnovers as a rookie in 2018. The sack total remains a career best. In 2023, he went 45-28-11 with 6 forced fumbles and 2 recoveries for the best statistical production of his career. Between 2018 and 2023, Chubb missed 19 games with one full season, and he was banged up for much of that one. He missed all of 2024, coming back to go 24-23-8.5 for Miami last year.
If the 30-year-old Chubb can stay on the field, he has the potential to put up strong numbers, but even when healthy, that is not a sure thing. He's worthy of a roster spot as depth with big upside, but we don't want to count on him as an every-week play.
Greg Rousseau will be the man opposite Chubb. The 2021 first-round pick of the Bills has been a steady contributor with at least 5 sacks in each of the last four seasons and 32 for his career. Over his first three years, Rousseau was held back by a lack of playing time. He was the starter, but the Bills used a rotation that kept everyone's snap count down. In 2024, he was on the field for 735 plays and had his best production at 36-17-8 with 3 batted passes and 4 turnovers. It was his first and only top ten. He is capable of getting back there. The big question is how well Rousseau will make the transition.
This is a similar situation to Carl Granderson last year. At 6'6" and 266 pounds, Rousseau has the length and wingspan that 3-4 coaches love, but he is used to trench warfare. He could shed a few pounds and excel, or he could struggle. The one thing we should see is enough playing time for snap count to not be a major factor.
Veteran Michael Hoecht and rookie TJ Parker will work behind the starters. Hoecht is an interesting prospect. The former Ram went from nearly 300 pounds as a defensive tackle to playing the edge when Los Angeles was hammered by injuries in 2022. He began shedding weight and had a productive 2023, going 43-34-6 with a forced fumble. After returning to a backup role in 2024, he signed with the Bills ahead of last season.
Hoecht missed virtually all of last year with an Achilles injury. He is expected to be ready for the season, though he could be limited early in camp. He's trimmed down to 264 pounds now, and could make the transition successfully.
Parker has the advantage of being selected by the current coaching staff, who believe he will be a good fit. He can get after the passer, as evident from his 11 sacks for Clemson in 2024, but his biggest asset is the ability to shed blocks and make plays as a point-of-attack run defender. Parker's best numbers came as a sophomore when he put up 57 tackles with those 11 sacks. He slipped back to 37 stops and 5 sacks as a junior before entering the draft. Parker is young, turning 22 in September, and is unlikely to make a significant immediate impact, but the organization sees him as a future starter.
No Buffalo tackle recorded more than 17 solo stops or 3 sacks in 2025. Pay zero attention to those numbers as they are irrelevant. The player to target here is Ed Oliver. The seven-year veteran totaled 10-2-3 with a forced fumble last year, so most managers will not give him a second thought. Considering he put up those numbers on 108 plays over three games, you don't want to be one of those managers.
Oliver had three separate injuries in 2025, all requiring some sort of procedure/surgery. He spoke about the injuries back in May at the team's OTAs, saying he was fully recovered and ready to roll. Oliver missed a handful of games in 2024 as well, so there is some injury risk. The last time he played a full slate of games, he went 34-17-9 with a takeaway in 2023.
Oliver and last year's second-round pick T.J. Sanders will be the outside tackles, with last year's fourth-round selection Deone Walker working at nose tackle. Walker had the best tackle numbers of the interior guys last season at 17-22-1 with 4 swatted passes. Sanders didn't play much as a rookie, but he had 93 tackles and 8.5 sacks as a two-year starter for South Carolina in 2023 and 2024, so there is potential. Walker could give us decent tackle totals, but he will likely come off the field in most passing situations.
- Edge Greg Rousseau – Unknown commodity in the new scheme
- Edge Bradley Chubb – High ceiling with considerable injury risk
- Edge TJ Parker – Dynasty target
- Edge Michael Hoecht – Watch list worth injury sleeper
- Edge Mike Danna – No impact
- Edge Landon Jackson – No impact
- Edge Javon Solomon – No impact
- DT Ed Oliver – Potential stud with some injury issues
- DT T.J. Sanders – Watch list deep sleeper
- NT Deone Walker – No grand expectations
- DT Zane Durant – No impact expected
- DT Phidarian Mathis – No impact