Borland retires at 24, citing health concerns
49ers' Chris Borland, 24, quits NFL over concussion worries
Chris Borland Announces Retirement From NFL At 24 Over Concussion Fears; NFL Has Mixed Emotions
The NFL Tried To Drug Test Chris Borland A Month After He Retired From The League
Chris Borland's Retirement an Uncommon Choice—but One NFL Players Understand, News, Scores, Highlights, Stats, and Rumors
49ers' Borland retires after rookie year over head trauma fears – Santa Cruz Sentinel
NFL: Players call it quits in prime of careers
NFL: Early retirements over health fears may have ripple effect
Chris Borland's Retirement Will Trigger Player Debate On Risk Of Future Dementia
Is Chris Borland's retirement the beginning of the end for the NFL? (updated) - The Washington Post
How San Francisco 49ers' Chris Borland made his decision to retire over safety concerns - ESPN
Badgers football: Former UW great Chris Borland retiring from NFL after only one season, citing head injury worries
Chris Borland retires from NFL at just 24 years old, makes his own sense of head injuries – New York Daily News
Chris Borland to retire from NFL, fearing concussions