Another coach leaves Buffalo Bills as team transitions to three new coordinators

Ryan Nielsen departs for Minnesota Vikings after middling results with Bills' defensive line

Jan. 31, 2026 at 4:47pm

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The Buffalo Bills have lost another coach as they transition to three new coordinators under new head coach Joe Brady. Ryan Nielsen, who served as a senior defensive assistant with the Bills this past season, is departing to join the Minnesota Vikings as their defensive line coach and defensive run game coordinator. Nielsen's tenure in Buffalo was marked by middling results, as the Bills' run defense struggled and the pass rush failed to improve significantly from the previous season.

Why it matters

The Bills are undergoing a major coaching overhaul, with Brady taking over as head coach and the team hiring new coordinators on offense, defense, and special teams. Nielsen's departure is the latest in a string of changes, as the organization looks to get the team back on track after a disappointing season.

The details

Nielsen joined the Bills this past offseason after previously serving as the defensive coordinator for the Jacksonville Jaguars. However, his impact on the Bills' defensive line was limited, as the team's run defense ranked fifth-worst in the NFL and the pass rush only marginally improved from the previous season. With his former boss in Jacksonville, Doug Marrone, being let go by the Bills, Nielsen has now decided to join the Vikings, where he will work under defensive coordinator Brian Flores.

  • Nielsen joined the Bills as a senior defensive assistant prior to the 2025 season.
  • The Bills finished the 2025 season with the 5th-worst run defense in the NFL, allowing 136.2 yards per game.
  • On January 31, 2026, Nielsen departed the Bills to join the Minnesota Vikings as their defensive line coach and defensive run game coordinator.

The players

Ryan Nielsen

A former defensive coordinator for the Jacksonville Jaguars who joined the Buffalo Bills as a senior defensive assistant in 2025, but is now departing to take a job with the Minnesota Vikings.

Joe Brady

The new head coach of the Buffalo Bills, hired after the team fired former head coach Sean McDermott.

Brian Flores

The defensive coordinator for the Minnesota Vikings, who will be working with Ryan Nielsen in his new role.

Doug Marrone

The former head coach of the Jacksonville Jaguars, who was let go by the Buffalo Bills.

Jim Leonhard

The new defensive coordinator for the Buffalo Bills, hired by new head coach Joe Brady.

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What they’re saying

“Jim's vision of what he wants from our defense and the personality they play with is the exact style of what I was looking for from a defensive coordinator.”

— Joe Brady, Buffalo Bills Head Coach

What’s next

The Bills will continue to fill out their coaching staff under new head coach Joe Brady, as they look to rebound from a disappointing 2025 season.

The takeaway

The Buffalo Bills are undergoing a major coaching overhaul, with the departure of Ryan Nielsen the latest change as the team transitions to three new coordinators under new head coach Joe Brady. The organization is hoping these changes will help improve a defense that struggled mightily in 2025.