How Jim Leonhard’s Defense Could Reshape the Buffalo Bills Roster in 2026

Sean McDermott built a defense on discipline and containment. Jim Leonhard builds his on pressure and disruption. That philosophical shift could fundamentally reshape the Buffalo Bills roster. Where Sean McDermott’s main philosophy was bend, don’t break, Jim Leonhard‘s is attack and break your opponent. The biggest challenge Jim Leonhard will face is who on this roster has the skill set and profiles to fit the roles available in the new look defense. How long will the transition take? Which current Bills players will benefit the most from the scheme change?

Jim Leonhard’s Defenses

The first place to look are to Jim Leonhard’s defenses of the past. Jim Leonhard was the Defensive Coordinator for the Wisconsin Badgers from 2017-2022. During his first season, he largely inherited the defensive makeup and roster, so for analysis purposes, we’ll include only those starting players he had a hand in recruiting. He then took a year off from coaching and spent a season with Illinois as a consultant, before joining the Denver Broncos as passing game coordinator under Vance Joseph in 2024, before adding the title of Assistant Head Coach in 2025.

Defensive End

As is the trend in most positions we will cover, Defensive End in Leonhard’s system had almost two distinct positions. RDE tended to be a bit smaller, playing 5 technique more often, lining up outside the tackle and sharing responsibilities with the Sam LB. They ranged from 6’2-6’4 and 273-293 lbs, with an average of 6’3 and 283 lbs. The skill set requires flexibility as his simulated pressure scheme asks Ends to drop into coverage frequently, but also to set the edge, play the run, and fill gaps along the line.

The other LDE, tended to be bigger and lined up more often in the 4i technique, specifically on running downs, lined up on the inside shoulder of the Right Tackle. They ranged from 6’3-6’7 and 288-323 lbs, with an average of 6’4 and 299 lbs.

The Broncos teams Leonhard coached on included 7-8 DEs out of the 53 who made the final roster.

With this in mind, the only Buffalo Bill that was on the Bills active roster at the end of 2025 slotted as a Defensive End that fit this prototype was Joey Bosa. Bosa not only has never played as a 3-4 DE, serving more as an 4-3 EDGE, but he is also a free agent in 2026 and seems unlikely to return to the Bills for a reshaping project, and will likely look for interest from teams in Florida where his family lives, if he decides not to retire altogether.

However, looking at DTs who will likely transition to DE, there are 2 players who fit the criteria and figure to be core pieces moving into 2026.

• Ed Oliver – 6’1 287lbs
• T.J. Sanders – 6’4 297 lbs (Read more on Sanders here)
• Greg Rousseau – 6’6 -286. Will Leonhard’s new scheme unlock Rousseau’s strengths. He’s rangy, and a savvy lineman at picking up runs and filling gaps, and even rushing the passer. Where the Bills have been frustrated by his lack of sack production, his ability to create pressure, to bat down balls, and to be solid at setting the edge and progressing through blocks. Leonhard worked with future Steeler’s DE Isaiahh Loudermilk at Wisconsin who plays at 6’7 274, so players with this size have a track record of success. If Rousseau subs into the rotation, look for him to pair extremely well with Deone Walker in Indy and Bench Fronts where they can line Greg up wide in the 5, 7 or 9 techniques and line Deone in the 4i or 3techniques (This article discusses past questions about Rousseau’s role in NFL Defenses)
• Deone Walker – 6’7 335 lbs. I’ve heard many commentators discuss Deone Walker‘s role moving forward as a DE, specifically as a 4i, but the trouble with that is that Leonhard has never coached a player this big as a DE…ever… and part of my confusion is that they will sometimes discuss 4i as though it is a position, but it’s not. 4i is an alignment that the DE shifts into specifically when facing 11 or 12 personnel in Leonhard’s Defenses. But those same DEs line up either aligned with or outside the tackle just as often depending on play call. In a 4-2 nickel, which Leonhard calls 30% of the time, one DE slide in to play what we’re used to as a 3 tech DT. As Leonhard, has a track record of breaking the mold for great play (see Pat Surtain) Deone could absolutely thrive in that Calais Campbell 3-4 DE mold, and just may, but it would be the first time anyone that big had ever played DE under Jim Leonhard in his entire career. (Read more on Deone Walker here)

This is a huge gap in the defense that will need filling as having 4 players will look good for a starting lineup, but will need an additional 3-4 players added that fit this profile.

Roster Gap Count: -4 new players needed

Nose Tackle

This position was fairly consistent. Big, stable, and able to anchor or penetrate. Take on double teams, and beat your man. Throughout Leonhard’s teams, NT ranged from 6’0-6’4 and weighed 305-347 lbs, and the average size was 6’2 and 315 lbs.

The Broncos during Leonhard’s tenure carried 3 true NTs on the 53 man roster.

On the 2025 roster, the Bills had plenty of guys who could fit this profile, all but 1 are now free agents. DaQuan Jones, Larry Ogunjobi, Phidarian Mathis will likely all test free agency, leaving the Bills undecided at the position. Only 1 current Bills player who made the 53 last year even fits the mold at all, and one player has major question marks.

• DeWayne Carter – 6’3 305 lbs. Carter is the clearest fit as a beefy NT that can anchor and eat up double teams, but his injury history and lack of penetrative production continues to be a concern.
• Zion Logue – 6’6 314 lbs. Currently signed to a futures contract, Logue is unproven, but could fit nicely with his prototypical size.
• Tommy Akingbesote – 6’4 314 lbs. Also signed to a futures contract, Akingbesote was a UFA out of Maryland where he played in a multiple scheme. He is likely a practice squad player, but let’s see what he looks like on the 90 man roster in the summer.
  

This would also widen another gap in the defense that will need filling. If they slot Deone Walker into a DE role, it would fill a gap in the 5-6 players needed, but would leave Buffalo without only one player who could be a true NT at all on the roster, elevating it to one of the biggest gaps on the current roster. Look for the Bills to sign/draft 1-2 true NTs this offseason.

Roster Gap Count: -6 new players needed

Sam Linebacker

This is your typical pass rusher that often creates stars like Von Miller, Kyle Van Noy, and Zach Baun. In Leonhard’s simulated and creeper pressure schemes, the Sam will often rush the passer, drop into coverage and set the outside edge when the DE shifts into 4i alignment. Leonhard usually prefers this to be the bigger of the two linebackers, ranging from 6’2-6’4 and 225-257, with an average of of 235. They are typically long rangy players, but versatile.

On the current Bills roster, this is yet another position, where the projection gets difficult. If you ask who the best pass rusher, who can also cover the run, and even drop into passing lanes, the answer is obvious, but difficult, as he doesn’t really fit the profile of a Sam LB in a Leonhard defense.

• Michael Hoecht – 6’4 270 lbs. The versatility and aggressiveness combined with his experience in 3-4 schemes during his time with the Rams makes Hoecht the perfect candidate for a seamless transition. The only hiccup is the size, as Leonhard tends to prefer guys that are smaller than Hoecht has ever played. He already dropped about 45 pounds to convert from DE to a traditional Rams OLB, so asking him to drop more is a bit of a reach. (Read more on Michael Hoecht here)
• Javon Solomon – 6’1 – 247. Solomon slots in well as a prototypical size guy, and is well thought of in the building. He has flashed in a lot of versatile ways, and could benefit in playing a role at Sam.
• Landon Jackson – 6’6 – 264 lbs. Jackson struggled greatly in the offseason of his rookie year, and suffers from the same scheme fit as Greg Rousseau, though he also shares the characteristics of long and rangy and was drafted based on his acumen as an edge rusher. While he doesn’t have the contract implications Rousseau does, he is still playing out his rookie deal. (Read more about Landon Jackson here)

Roster Gap Count: -7 new players needed

Jack/Bandit LB

Typically a little smaller than Sam LB, though the difference is pretty marginal,the Jack/Bandit is an outside linebacker that typically will also rush the passer, jump down to the line of scrimmage on simulated pressure and will fill gaps on the DL, but also drop into coverage and will play to the weak side of the field. Under Leonhard, this player ranged from 6’2-6’3 and 230-243 lbs, with an average of 6’2 237 lbs.

The current roster does have some players that fit that mold, including some promising fan favorites:

• Dorian Williams – 6’2 – 230 lbs
• Joe Andreesen – 6’1 232 lbs (Read more about Joe here)

If the Bills wanted to bring back some former players, Shaq Thompson and Baylon Spector fit the size threshholds, with Shaq being the most interesting given his performance from this past season.

Overall, the Broncos rosters under Leonhard carried 6 total OLBs on their 53 man roster. Look for the Bills to add at least 1 more player at this position that will make the team come September.

Roster Gap Count: -8 new players needed

Mike/Will Linebacker

These two positions tended to be somewhat interchangeable, though there was almost always a player who would rush the passer more often than the other. These are the type of linebacker that we are more used to as Bills fans, somewhat smaller than the Sam, but bigger than the Jack/Bandit, capable of zone coverage and running with TEs and RBs. Leonhard’s inside linebackers ranged from 6’0-6’2 and 225-250 lbs with an average of 6’1 and 235 lbs. Given the similarities to the linebackers from the 2025 season, the Bills will have pretty good continuity options as their current players fit the profile fairly well, though aging player and pending free agency may make this more of a priority add in the upcoming offseason.

• Terrel Bernard – 6’1 – 224 lbs
• Jimmy Ciarlo – 6’2 – 225 lbs
• Keonta Jenkins – 6’3 – 219 lbs

Joe Andreesen and Dorian Williams could also slot into these positions, though Terrel Bernard is a cleaner match for this position. If Matt Milano wants to run it back, he could be a great fit alongside Bernard as the twin ILBs. Leonhard’s defenses have carried 6 ILBs on the 53 man roster, so look for the Bills to add 3 more linebackers to make the final roster.

Roster Gap Count: -11 new players needed

Outside Cornerback

Cornerbacks in a 3-4 versus a 4-3 don’t necessarily have to have differing skill sets, though in Jim Leonhard’s schemes coverage is often based upon the skill sets the corners excel at. Some years, cover 1 press dominated, while in other Cover 3, and bracket coverages were more common. Corners ranged from 5’10-6’2 and typically ranged from 184-197 lbs, with the exception being all-pro Pat Surtain III, who can be whatever size he wants to be, and would still start for every team in the league. The average CB was 6’0 and 193 lbs.

With this in mind, the Bills are in a good spot at this position, with both starting CBs excelling at man coverage and zone play, though their depth could use some work. the Broncos carried 5 outside CBs on the 53 man roster.

• Christian Benford – 6’1 – 205 lbs
• Mad Max Hairston – 5’11 – 183 lbs (Read more about Max here)

It’s unclear whether Dorian Strong‘s recent surgery was successful and will allow him to return to action next season, but if he does, he would represent necessary depth at the position. Current practice squad players that will have a chance to show out in the summer include M.J Devonshire, Daryl Porter Jr. and possibly even Dane Jackson, though he is likely a McDermott faithful that will find another home in the future. With only 2 roster locks, look for the Bills to add to the 90 man roster and have a competition for the 3 more spots available.

Roster Gap Count: -14 new players needed

Nickel CB

Leonhard’s defenses have always employed a nickel CB that will come onto the field when the offense shifts into 3-5 WR looks. This CB is almost always slighter and quicker than their outside counterparts. They ranged from 5’9-5’11 and 176-183 lbs, with an average of 5’10 and 181 lbs. His Broncos team carried 2 of these particular players.

The Bills have only one nickel on the roster, with another on the practice squad who might challenge for one of these two positions

• Taron Johnson – 5’11 – 192 lbs. For the first time in 6 years, Taron Johnson is not a clearcut prototype nickel CB in his defense. His flexibility as a quick inside corner and track record with the Bills, combined with his durability and tackling prowess will go a long way with Jim Leonhard. But his size may put him in an awkward position as he is almost 10 lbs bigger than even the biggest of Leonhard’s typical nickel CBs. His current contract doesn’t end until 2028, so look for him to adjust to the new scheme.
• Te’Cory Couch – 5’10 – 175 lbs. Being only a practice squad player, Couch will be likely be given a chance in the summer to compete for the job.

Look for the Bills to add competition to this position and possibly look for Taron Johnson’s eventual successor.

Roster Gap Count: -15 new players needed

Strong Safety

This is another position in which the typical 3-4 scheme has a clear Strong Safety and a clear Free Safety serving completely different roles in the defense.

The Strong safety is typically shorter and stockier, coming down into the box to serve as an additional linebacker, or creeping down into the strong side of the field, teaming up with the Sam LB to take on TEs coming up to block. This player ranges from 5’10-6’1 and 198-211lbs, with an average of 6’0 and 201 lbs.

This projection is as clean as it comes as they have the prototypical starter already on the roster.

• Cole Bishop – 6’2 – 207 lbs. Cole Bishop is a big winner as he will fit perfectly into what Leonhard likes to do. Aggressive, eager for contact, yet still with good ball skills, Bishop will appeal perfectly to the former standout safety in Jim Leonhard.
• Taylor Rapp 6’0 – 208 lbs. This was one of the problems we foresaw last season and seemed to come to pass, in that the Bills seemingly had two Strong Safeties, with neither fitting the Micah Hyde prototype. It seemed out of necessity, that McDermott played both Rapp and Bishop on the field at the same time, but it doesn’t seem like something Leonhard will entertain unless he has to. With Rapp only carrying a .6 mil cap hit, watch for him to be a cut candidate as he could clear 3 million in cap space.
• Wande Owens – 5’11 – 210 lbs. Playing on a rookie contract, Wande would be quality cost-controlled depth, assuming he is healthy going into 2026. (Read more about Wande’s history with the Bills here and here)

Roster Gap Count: -16 new players needed

Free Safety

The free safety in Leonhard’s schemes were typically taller, but rangier players, spanning 6’1-6’2 and 191-202 lbs. This is where the Bills roster will be in search of an answer for 2026 and looking for development from some of their younger players. The Broncos carried three players who fit this role on their 53 man roster in the fall.

The Bills only have unproven options currently on the roster and they include:

• Jordan Hancock – 6’0 -195 lbs. Jordan is the cleanest projection as a rookie who made the 53 man roster and came from a stellar program at Ohio State. The only trouble is that his calling card out of college was in his positional flexibility, as he would play outside corner, nickel and safety. This could be seen as a positive in a Leonhard scheme, though Leonhard may look to someone with more experience as a center fielder, with his propensity to like Cover 1 looks, with the FS responsible for the deep center of the field between the hashes. Hancock is in a great position to learn from one of the better young DB coaches on the rise in the NFL, but will need to step up to the task if he is to serve as the number 1 FS on the team. (Read more about Jordan here and here)

Look for the Bills to add veteran depth or another rookie to compete with Hancock for the starting FS spot.

Roster Gap Count: -18 new players needed

Outlook for 2026

While the hire of Jim Leonhard represents a meaningful move towards change and evolution, it creates a challenge for Brandon Beane to rebuild an entirely new defense that will fit Jim Leonhard’s vision. Unfortunately, with so many holes and a lack of cap flexibility, it will likely take more than one offseason to do so adequately. I am projecting needing to fill 18 positions with new players on the defensive side of the ball. While the Bills can free up cap space through a few key restructures and have 7 draft picks, they will likely be prioritizing guys who are familiar with Leonhard and also are cost effective options to compete for these 3-4 roles in this new defense.

Look forward to our next post in which we identify Free Agent candidates to fill the holes on the defensive side of the 2026 Bills roster.

Until then, read our breakdown on the hiring of new Receiver coach Drew Terrell.