Davis, who signed a one-year, $5 million contract with Buffalo in February after spending seasons with the Miami Dolphins and the Indianapolis Colts, said he meant “no disrespect” to his teammates and coaches and called the decision to retire “overwhelming.”
“I had an honest moment with myself,” he said, adding that he also wondered, “Do I want to keep sacrificing?”
He continued, “Truthfully, I do not because the season is long, and it’s more important to me and my family to walk away healthy than to willfully embrace the warrior mentality and limp away too late.”
After playing all but 13 games in his first eight seasons, Davis missed 11 last year because of a lingering groin injury. He had at least three concussions in his N.F.L. career, along with a broken wrist and hamstring and knee and foot sprains. Davis was healthy but inactive in Week 1 — a 47-3 loss to the Baltimore Ravens.
In recent years, as more information has emerged about the connection between repeated blows to the head and the degenerative disease known as chronic traumatic encephalopathy, some players have chosen to retire despite remaining productive on the field.
San Francisco 49ers linebacker Chris Borland retired in 2015 after a successful rookie season, saying, “From what I’ve researched and what I’ve experienced, I don’t think it’s worth the risk.” Baltimore Ravens guard John Urschel accepted that risk for three seasons before retiring at 26 to pursue a career in high-level mathematics.
Players have also occasionally decided to leave the field abruptly.
In 2013, wide receiver Dez Bryant walked to the locker room with 1:21 remaining and his Dallas Cowboys trailing by 1 point. They lost after leading the Green Bay Packers by 23 at halftime, and Bryant later wrote on Twitter that he had left the game because he was emotional. “It had nothing to do with my teammates,” he said.