Chris Borland retires from NFL aged 24
49ers ex-linebacker Chris Borland salutes Pat Tillman
49ers linebacker Chris Borland's decision to retire may be start of silent revolution
Chris Borland Comments on Concussions, Retirement and More, News, Scores, Highlights, Stats, and Rumors
NFL concussions: Alter grad Chris Borland speaks out about Tua Tagovailoa injury
Taylor empathizes with Borland's life decision
49ers Linebacker Quits After 1 Season, Citing Safety Concerns : The Two-Way : NPR
Is fear of injury pushing NFL players like Borland out?
Full transcript of Tim Ryan's comments regarding Chris Borland retirement - Niners Nation
More players are calling it quits in prime of their careers, Sports