49ers ex-linebacker Chris Borland salutes Pat Tillman
Chris Borland, San Francisco 49ers linebacker, retiring due to head trauma concerns - Newsday
49ers linebacker Chris Borland shocks NFL with decision to retire after one season
49ers star Borland, 24, retires over health concerns
49ers' Chris Borland retiring at 24, wary of head trauma, Sports
49ers' Chris Borland retiring at 24, wary of head trauma – The Denver Post
Why the NFL needs to worry about Chris Borland
Retiring 49er Chris Borland to pay back NFL signing bonus - Sports Illustrated
49ers Chris Borland retires from football, citing concern over head injuries - Field Gulls
San Francisco 49ers Linebacker Retires At Age Of 24
San Francisco 49ers Chris Borland Retiring at 24, News
Borges: NFL takes big hit with Chris Borland”s retirement – Boston Herald
49ers' Chris Borland retires: NFL responds, cites safety progress - Los Angeles Times