Retired 49ers lineman Joe Staley hailed by Willis, ex-teammates
Patrick Willis Explains Decision to Retire from NFL
49ers news: Why Patrick Willis should be a lock as first ballot Hall of Famer - Niners Nation
Patrick Willis Explains Decision to Retire from NFL
How NFL players are thinking about life after football - ESPN
NFL star Chris Borland quits over head injury concerns - CBS News
10 Athletes Who Retired in Their Prime
Early retirement: Willis called it quits in his prime
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