Patrick Willis Explains Decision to Retire from NFL
Patrick Willis - Wikipedia
Patrick Willis - Wikipedia
A Sign of the Future? Concussions Push NFL Players to Retire Early
Biggest Retirements of 2015 - Sports Illustrated
Chris Borland retirement from 49ers shows shift in attitude
Retired 49ers LB Patrick Willis denies report of 2016 comeback
A Sign of the Future? Concussions Push NFL Players to Retire Early
Patrick Willis to retire after 8 seasons with San Francisco 49ers
Patrick Willis retiring from 49ers after injury-shortened season