The move was announced by the team in a one-sentence news release as the Bills prepared to return to practice following a two-day break.
Merriman's release was regarded as a mild surprise for a player who described himself as being in his best shape in years after having season-ending surgery in November to repair a partially torn right Achilles tendon. It's an injury that had nagged him for much of the previous two seasons.
The Bills had also kept their faith in Merriman, believing he had an opportunity to play a key backup role on a defensive line that was revamped in free agency this offseason with an eye on pressuring opposing quarterbacks. Buffalo signed defensive end Mario Williams to a six-year, $100 million contract, then landed pass-rushing defensive end Mark Anderson.
Merriman had spent much of training camp backing up both Williams and Anderson.
Although Merriman missed a few practices nursing a twisted ankle, the Bills gave no indication that his job was in jeopardy.
Merriman was credited with three tackles in two preseason games. He had one tackle and played with the backups well into the second half of Buffalo's 36-14 loss at Minnesota on Friday.
The seventh-year player was entering his third season in Buffalo. The Bills claimed him off waivers after he was cut by San Diego in November 2010.
He finished the 2010 season on injured reserve after aggravating the injury to his Achilles tendon a half hour into his first practice with Buffalo. Merriman had two sacks in five starts with the Bills last season before landing on I.R. to have surgery on his Achilles and also repair a nagging shoulder injury.
Merriman, on numerous occasions this offseason, suggested he felt rejuvenated.
"I feel young," Merriman said in May. "Anybody that will get a chance to watch me this year will see I'm moving around as I did when I came into the league."
At his peak, the three-time Pro Bowl selection was regarded as one of the league's top pass-rushers and earned the nickname "Lights Out." He was the NFL's 2005 defensive rookie of the year after being drafted 12th overall by San Diego.
Merriman had 39 1/2 sacks through his first three seasons before injuries slowed his production. He combined for just six sacks in his past four seasons, a stretch in which he appeared in only 23 games.