James Harrison is hanging up his spikes for good. The longtime Pittsburgh Steelers linebacker announced on Monday that he is retiring from the NFL. Harrison made the announcement via his Instagram account. 

"I've missed way too much for way too long...and I'm done. Many thanks to my family, coaches, the fans, and everyone who played a role in my football life. #2ndAndFinalRetirement #HarrisonFamilyValues #BlessedAndHighlyFavored #GodsPlan 🙏🏾," he wrote in a caption. 

Harrison ends his career having played 15 NFL seasons, 14 of them with Pittsburgh. He recorded 84.5 sacks throughout his career, and for a time was one of the most fearsome pass-rushers in the NFL. From 2007 through 2011, only DeMarcus Ware, Jared Allen, Trent Cole, and John Abraham recorded more sacks than Harrison, who had 54 quarterback takedowns during that stretch. 

Harrison became a bit less effective as he got up there in age, but he was still a valuable situational rushman. He also became widely-known for his incredible weight-lifting exploits, which are practically the stuff of legend at this point. Harrison's Pittsburgh career did come to an ignominious end last season, as he played only 40 snaps across five of the team's first 14 games of the regular season before being granted his release. Harrison immediately caught on with the rival New England Patriots and helped them reach the Super Bowl, recording three sacks, seven hurries, and three additional quarterback hits in four games with the team while also playing excellent run defense. 

It would appear Harrison has something left in the tank, but apparently he has decided that it's time to call it quits.