Early retirement
A.J. Tarpley is one of a number of promising young NFL players recently who have ended their careers early because of health concerns. Others include:
Chris Borland: 49ers' third-round pick out of Wisconsin in 2014 started eight games at linebacker in his only season.
Jason Worilds: Steelers LB retired at age 27. He had 25½ sacks in five seasons.
Jarod Mayo: 2008 defensive rookie of the year retired from the Patriots at age 29.
Patrick Willis: Seven-time Pro Bowl LB for the 49ers said his body was wearing out.
