Ian Rapoport of NFL.com reported last month that the 25-year-old Martin would retire rather than undergo back surgery and potentially miss the 2015 season.
Martin started nine games for the 49ers last season and was waived in March. The next day, the Panthers claimed the offensive tackle off waivers.
As a rookie in 2012, Martin started all 16 games for the Miami Dolphins. He started seven games for Miami in 2013 before accusing teammate Richie Incognito of bullying him, prompting an investigation into the Dolphins' locker room culture. Incognito received an eight-game suspension.
Gonna miss football... Was always my dream to play in the NFL. Proud to say I did it, the right way, even if for not as long as I wanted— Jonathan A. Martin (@J_Martin71) August 10, 2015
Nothin but love for my Panthers & 49ers teammates— Jonathan A. Martin (@J_Martin71) August 10, 2015
According to Black and Blue Review, Martin also tweeted and deleted, “But, in the end, football was just a job, albeit a fun and well-paying one. Being in a wheelchair at age 50 isn't worth any amount of money.”