[3] The Bills and Erie County (the owners of Ralph Wilson Stadium) missed the deadline for a long-term agreement in September 2012;[4] however, on December 21, the Bills agreed with Erie County to a 10-year lease on Ralph Wilson Stadium, extending it for at least another seven years.

[5] On January 2, 2012, one day after the conclusion of the season, George Edwards was fired from his position as defensive coordinator.

In his annual season-ending press conference, general manager Buddy Nix laid out his priorities for the offseason.

Nix stated that the team was eager to re-sign wide receiver Stevie Johnson, kicker Rian Lindell and offensive tackle Demetress Bell.

[7] On March 15, 2012, the Bills made the biggest free agent acquisition in team history, signing all-pro defensive end Mario Williams to a contract worth $100 million over six years, with $50 million guaranteed, the largest contract for a defensive player in NFL history.

On March 21, 2012 Mark Anderson, who had 12.5 sacks with the Patriots over the 2011 regular season and playoffs, signed a four-year deal with Buffalo.

[9] With announced plans to switch to the 4–3 defense the Bills could field Mario Williams at left end and Anderson on the opposite side in passing situations.

He was nonetheless released in the middle of the preseason, with Gailey citing inconsistency as the reason, and replaced by Tarvaris Jackson, whom the Bills acquired in a trade with the Seattle Seahawks.

He will specialize in kickoffs to ease pressure on the team's aging kickers, placekicker Rian Lindell and punter Brian Moorman, who handled the duties in the past.

By beating the Dolphins on a Thursday Night Football showdown, Buffalo improved to 4–6 and snapped an 8-game losing skid against division rivals.