Report: 49ers' Patrick Willis planning to retire
Is Chris Borland an outlier or the start of a trend? With concussion risks still uncertain, it's tough to say
Patrick Willis still thriving after early 49ers retirement
Patrick Willis Retired in His Prime, But Where is He Now? - FanBuzz
Patrick Willis Explains Decision to Retire from NFL
Patrick Willis Announces Retirement from NFL
49ers: Patrick Willis offers retirement advice for Joe Staley
49ers' Patrick Willis retires 'happy' – The Mercury News
49ers' Patrick Willis retires 'happy' – The Mercury News
Patrick Willis to retire after 8 seasons with San Francisco 49ers - Niners Nation
Patrick Willis Explains Decision to Retire from NFL
Senior Bowl to Induct Patrick Willis and Four Others into Hall of Fame
Is Chris Borland an outlier or the start of a trend? With concussion risks still uncertain, it's tough to say