Is fear of injury pushing NFL players like Borland out?
Longtime Steelers cornerback Ike Taylor retires at 34, Sports
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NFL community reacts to Chris Borland's retirement
Steelers linebacker Jason Worilds shuns big NFL free agent contract, opts to retire at 27 – New York Daily News
49ers among biggest hit by early retirements of Borland, Anthony Davis, Willis
Griffin Campaigning for Brian Orakpo To Join Tennessee Titans. - Hogs Haven
NFL players who retired before age 30: Percy Harvin joins list
Chris Borland, Fearing for Health, Retires From the 49ers. At 24. - The New York Times
Lowell Cohn: Chris Borland's retirement a choice to admire