Ed Oliver, Greg Rousseau Are Two Bills Holdovers Most Important for Jim Leonhard's Defense

Two of the Bills' former first-round picks must step up to the plate and perform for the Buffalo resistance to reach its full potential.

Defensive linemen Greg Rousseau, (50), left, and Ed Oliver, (91), right, joke around at Bills practice. | Shawn Dowd / USA TODAY NETWORK

Of the 40 players returning to the Buffalo Bills’ roster in 2026, two are most critical in the team’s effort to transition to a new defensive scheme under first-year defensive coordinator Jim Leonhard.

Leonhard is expected to deploy a 3-4 base defense that features multiple fronts aimed at creating chaos in terms of its pass-rush ability and an increased turnover rate. Defensive tackle Ed Oliver and edge rusher Greg Rousseau, both former first-round picks, each possess skill sets at their respective positions that will be vital for the Bills to establish the groundwork they hope will lead to immense success moving forward.

Oliver exploded before injuries last year

Bills defensive tackle Ed Oliver cuts around a blocker as he puts in work alone on the practice field during the second day of Buffalo Bills training camp. | Shawn Dowd/Rochester Democrat and Chronicle / USA TODAY NETWORK via Imagn Images

Despite dealing with two significant injuries a season ago, when he was on the field, Oliver was incredibly productive.

In only three games played, Oliver finished with three sacks, seven tackles for loss and a forced fumble. He also received a Pro Football Focus pass-rush grade of 66.2 and an even more impressive run-defense grade of 90.4.

If over a full 17-game schedule he can deliver the level of production that he did during his abbreviated stint last season, the Bills’ pass rush will have the interior disruptor it needs to wreak havoc on opponents.

Rousseau is the edge-setter Bills need

Buffalo Bills defensive end Greg Rousseau (50) makes a catch during Minicamp at Highmark Stadium. | Gregory Fisher-Imagn Images

One of the Bills’ goals this offseason was clear—strengthen the team’s ability to set the edge defensively in hopes of better slowing combative rushing attacks.

The Bills allowed the third-highest EPA per run play allowed [+0.05] in 2025, according to NFL Pro, behind only the New York Giants [+0.12] and Dallas Cowboys [+0.06]. That led to them allowing 24 rushing touchdowns, tied with the Cowboys for the most in the league.

While the team as a whole struggled in run support, Rousseau was a stalwart in that area. The 6-foot-6, 266-pounder’s PFF run-defense grade of 83 was second among 115 graded edge defenders in 2025.

With Rousseau leading a much-improved group of edge defenders, which includes free-agent acquisition Bradley Chubb and rookie T.J. Parker, Buffalo is in a great position to rebound from a down year of run defense. And it must show dramatic improvement if it hopes to enjoy an uptick in production under Leonhard in his first season at the helm.

Changes are coming to Buffalo’s resistance, but it’s two players who have stuck around from the previous regime who are incredibly important to the team’s quest for greatness in 2026.