Bradham entered training camp slated as the starting weakside linebacker. He received the opportunity to become the starter after Kiko Alonso tore his ACL during organized team activities, Arthur Moats departed in for the Pittsburgh Steelers in free agency, and Manny Lawson was moved to defensive end. On July 30, 2014, Bradham received a one-game suspension stemming from his marijuana possession charge he received in August 2013 (see personal life). Head coach Doug Marrone officially named him the starting weakside linebacker to start the regular season, alongside starting strongside linebacker Keith Rivers and middle linebacker Brandon Spikes.
On September 21, 2014, Bradham collected a season-high 12 combined tackles (four solo) during a 22–10 loss to the San Diego Chargers in Week 3. In Week 4, he recorded four combined tackles, a pass deflection, made his first career interception, and 1.5 sacks in the Bills' 23–17 loss at the Houston Texans. Bradham made his first career sack on former teammate Ryan Fitzpatrick for a three-yard loss in the first quarter and intercepted a pass originally intended for running back Arian Foster by Ryan Fitzpatrick in the third quarter. He injured his knee while making the interception in the third quarter and missed the remainder of the game. The injury sidelined Bradham for the Bills' Week 5 victory at the Detroit Lions. In Week 13, Bradham recorded a season-high ten solo tackles and assisted on a tackle during a 43–23 victory at the New York Jets. On November 30, 2014, he tied his season-high of 12 combined tackles (nine solo), deflected a pass, and recorded a sack in the Bills' 26–10 win against the Cleveland Browns in Week 13. Bradham finished the 2014 season with a career-high 104 combined tackles (66 solo), six pass deflections, 2.5 sacks, and an interception in 14 games and 14 starts.