ORCHARD PARK, N.Y. -- The Buffalo Bills’ change in defensive scheme has been akin to a breakup.
Or at least defensive tackle Ed Oliver finds it to be an apt comparison.
“Everything you did in the last relationship, yeah, throw that all that away,” Oliver said. “This [is] a whole ‘nother person ... so you got to relearn.”
The unit is undergoing a massive change after previously being led by head coach Sean McDermott for the last nine seasons. Jim Leonhard has taken over as coordinator under Joe Brady and is in the process of implementing his vision during the team’s voluntary organized team activities (OTAs).
Oliver, who was drafted ninth overall in the 2019 NFL draft, has only played in an NFL defense under McDermott and grew comfortable in his scheme. While breakups can be difficult, Oliver is looking at the change as a new opportunity.
“It’s fun, it’s different,” Oliver said. “Change is always hard but sometimes change is good. I don’t know, I just look at it with that kind of optimism and just let it ride.”
Leonhard can get a better sense of the players’ comfort in the new defense during OTAs while still trying different ideas out. Leonhard is in his first defensive coordinator role in the NFL but spent six seasons in that position at Wisconsin (2017-22).
The excitement of the offseason for Leonhard comes from figuring out how he is going to blend the scheme he desires, as the team shifts from a 4-3 to a 3-4 base, with the skillsets of the players in the building.
“I had a vision for what I want it to be, and it might not totally get there in year one,” Leonhard said. “We have to be real as far as who we have, what their skill sets are, and I have to be flexible as well as them.”
Leonhard stressed that once the team gets into training camp and closer to the season, that is when they will dial in on what exactly the group will look like. He also acknowledged the unit may look very different from the beginning of the season to what it becomes later on.
To get to where he’d like the Bills to be, he is using an overload philosophy. That entails pushing extensive information on a player to make them uncomfortable and force additional communication.
For Oliver, a veteran who has been in one system for his whole career, Leonhard said that the new base defense will give him more freedom. “I think Ed’s gonna be really disruptive in this defense,” Leonhard said. “...I think he’s starting to see kind of where he fits and how he’s gonna fit and how we’re gonna be able to utilize him and create some one-on-ones and isolate some guards, which all defensive linemen get excited about.”
Oliver pointed to the success and freedom that defensive lineman Zach Allen has played with in Denver while Leonhard was on the Broncos defensive staff -- Leonhard was in Denver from 2024-2025 serving as the team’s defensive backs coach and pass game coordinator and then assistant head coach last year.
Allen recorded 40-plus quarterback hits and seven-plus sacks in both 2024 and 2025.
Oliver said that he hopes to garner similar success as Allen did last season. Oliver never really got going due to suffering two major injuries that led to playing in three games. He did not participate in Tuesday’s on-field work due to what he described as a “little oops-oops,” comparing his current injury to tripping as you walk out of a door.
But Oliver said that he’s overall healthy after a left ankle injury suffered during practice before Week 2 last season, a torn left biceps in Week 8 vs. the Carolina Panthers, and meniscus damage that came while rehabbing the biceps in December.
“I’m healthy and I don’t want to think about [last year’s injuries],” Oliver said. “So hey, I’m thankful for my health that I got now. ... Maybe this year will be different.”
Fellow defensive lineman T.J. Sanders said that he feels Leonhard’s defense will allow some Bills to play to their strengths more, in part because of those one-on-ones.
“Making guys actually have to block our guys one-on-one, and I feel like that’d be tough for any opponent,” Sanders said. “And that’s also a strength of ours. Letting guys one-on-one go tee off on the quarterback or run game. I feel like it’ll allow us to be great at both.”
Second-year cornerback Maxwell Hairston said he’s excited about “playing fast” in the defense, while linebacker Terrel Bernard, coming off an injury-ridden season of his own, said that what stands out to him the most is the ability to “be multiple.” Several players pointed out the freedom the defense will provide and how Leonhard’s football knowledge has stood out.
“We got a bunch of different fronts, a bunch of different personnels that we can use,” Bernard said. “And I feel like they try to get guys active, whether that’s an outside linebacker, an inside linebacker, a safety, a nickel. I feel like it’s been a little bit of everything right now.”
Getting to this point in Leonhard’s career has been intentional after three years away from a coordinator role. He was promoted from defensive coordinator to interim head coach of Wisconsin in 2022 when Paul Chryst was fired after five games. What he’s learned over the years since, including spending the 2023 season as a senior football analyst at Illinois, is now part of the vision that he’s excited to share with the room.
Self-described as someone who is not going to say something unless he has to, Leonhard has a quieter presence than former Bills defensive coordinator Bobby Babich, whose voice would often be heard echoing across a practice field. Leonhard said that for him, being quieter allows him to get to know a room better.
“Overlook me if you want to,” Leonhard said. “I’ve always had that kind of chip on my shoulder. So, [I] carry that on as a coach because I think it’s important to be who you are and if I’m trying to give a message, I think guys understand that it’s real ... I bring something to a meeting, they know I mean it.”
