Patrick Willis Explains Decision to Retire from NFL
NFL player's retirement at 24 prompts new debate about football
Olsen says Kuechly 'very at peace' with sudden retirement
Patrick Willis Explains Decision to Retire from NFL
Patrick Willis says his surprise retirement was the right decision
Patrick Willis Explains Decision to Retire from NFL
Chris Borland's early retirement shifts focus of head injuries in
Why early NFL player retirements actually make sense
Patrick Willis says his feet carried him away from the game
Chris Borland retires from 49ers after one year due to fears over
Patrick Willis, Justin Smith retiring from 49ers - NBC Sports
Patrick Willis Opens up About his Difficult Decision to Retire
Borges: NFL takes big hit with Chris Borland”s retirement – Boston