Hardwick, 33, spent all 11 of his NFL seasons with the Chargers. He appeared in one game this season after recurring neck issues forced him to injured reserve after the season opener.
Over 136 career games (all starts), Hardwick earned one Pro Bowl berth (2006) and was a five-time team captain.
"I got a fast track to life on a professional and personal development course," Hardwick said of his career, according to the U-T. "I feel like I have the wisdom of a 60-year-old in a 33-year-old's body, and I'm so thankful for that. Everything is so elevated in football. The highs are so high, and the lows are so low. … It's a big soul-searching journey. I'm really thankful that I guess I found the sport, and the sport found me.
Hardwick reportedly slimmed down from his listed playing weight of 305 pounds to 208 pounds. According to the U-T, Hardwick considered retirement last offseason before deciding 2014 would be his final season as he continued to deal with numbing and spinal issues.
"Nerves were getting compressed through various forms," Hardwick said. "My hands were going numb during training camp for weeks at a time. I was losing feeling in my fingers up through my elbows. I was having a bunch of stingers. On a daily basis, my hands were asleep, my elbows were burning, and I was losing a normalcy to life. It became reckless to continue playing. ...
"Physically, I'm not beating my head against a wall for a living, and that's a relief."
A former walk-on at Purdue, Hardwick was drafted in the third round of the 2004 draft.
The Chargers finished 9-7 in 2014, missing the playoffs for the fourth time in five seasons.
- Mike Fiammetta