BUFFALO, N.Y. (AP) -- Buffalo Bills linebacker A.J. Tarpley is retiring from football after just one season rather than risk suffering another concussion.
Not even one last visit to his locker stall at the Bills' facility could change his mind.
Tarpley's agent, Ryan Downey, confirmed his client's decision on Thursday, a day after Tarpley announced the news on his Instagram account.
"After months of introspection, I am retiring from football," Tarpley wrote. "I suffered the 3rd and 4th concussions of my career this past season and I am walking away from the game I love to preserve my future health."
Tarpley became the latest player to walk away from the game because of concussion concerns.
Last year, San Francisco 49ers rookie linebacker Chris Borland retired at the age of 24 by saying he wants to do "what's best for my health." Last week, Kansas City Chiefs safety Husain Abdullah cited health concerns in electing to retire after seven seasons, and after suffering his fifth concussion last year.
Tarpley signed with Buffalo as an undrafted rookie free agent out of Stanford. He had a sack and two interceptions in 15 games, including two starts, last season.
He was listed on the Bills' injury report for having a concussion just once in early November after he was hurt in a 34-31 loss to Jacksonville in a game played at London. Following the team's bye week off, Tarpley returned to play the next game.
"This is the hardest decision I've made yet, but after much research and contemplation I believe it's what is best for me going forward," Tarpley wrote, before thanking his family, teammates, former coaches, the Bills and their fans.
The Bills issued a statement saying Tarpley informed coach Rex Ryan about his plans to retire, but the team didn't know whether the player formally submitted the required paperwork to the NFL.
"He has expressed how difficult the decision was, and we certainly respect his decision," the Bills statement added. "We enjoyed having A.J. as a valued member of our team last year and wish him the best of luck in his future endeavors."
Tarpley is retiring despite knowing he had a chance to compete for more playing time in Buffalo after the team failed to re-sign starter Nigel Bradham and backup Ty Powell this offseason.
Downey, who helped his client write the four-paragraph message, said he and Tarpley's parents had been informed of the decision last weekend. Though Tarpley had been contemplating retirement since the end last season, Downey said the player didn't reach a conclusion until after he visited the Bills' facility in Orchard Park last week.
"He returned to Buffalo and was prepared to compete for playing time," Downey told The Associated Press. "He walked into the locker room and it wasn't enough to convince him."
At that point, Downey said Tarpley informed Ryan and his staff that he was not going to return to play.
"My first thought was kind of a shock," Downey said. "But my first reaction was for his safety and health, and making sure this is what he wanted. ... He was adamant that he gave it enough thought."