Top ten NFL early retirements – where does 49ers LB Chris Borland rank?

5. Chris Borland (LB, San Francisco 49ers)

One of the emerging stars in Jim Harbaugh’s elite defense, Borland was one of the best rookie defenders of the 2014 season, racking up over 100 tackles, Defensive Rookie of the Week and Rookie of the Month honors. But after citing long-term health concerns over the dangers of playing football, Borland abruptly called it quits – less than a fortnight after another teammate called it quits early….