2014 video reveals Cris Carter told NFL rookies they needed a 'fall
How many millions did 49ers' Chris Borland give up by retiring at 24?
Hard Truth On Wisconsin Magazine
San Francisco 49ers' Chris Borland Retires at 24 Over Concussion
Cris Carter feels heat over 'fall guy' comments - The Boston Globe
Borland retires at 24, citing health concerns
49ers' Chris Borland, 24, quits NFL over concussion worries
Chris Borland to retire from NFL, fearing concussions
Badgers football: Chris Borland's decision to step away still