Former Stanford and 49ers offensive lineman Jonathan Martin has decided to retire following a recent back injury, according to multiple reports.
Martin, 25, who was expecting to compete for a spot on the Carolina Panthers this summer, sustained an injury during a recent workout. He was told he could not have any activity for at least six weeks, FoxSports reported.
Martin becomes the fifth player from the 2014 49ers to retire this offseason, joining Patrick Willis, Chris Borland, Justin Smith and Anthony Davis.
The 49ers waived Martin on March 26 after he started nine games last season at right tackle in place of Anthony Davis.