Sting's wrestling career is over ... TMZ Sports has learned.
Long story short ... the wrestling legend messed up his neck real bad at his "WWE Night of Champions" match against Seth Rollins back in September -- and was never able to recover.
Sources connected to Sting tell us he was evaluated by several doctors who all agree -- it's just too risky for the wrestler to get back in the squared circle ... so, he's decided to hang up his singlet.
We're told the 56-year-old was formally diagnosed with cervical spinal stenosis -- a condition affecting the nerves that can result in extreme pain and discomfort.
In fact, it's the same condition that forced fellow WWE superstar Edge to retire in 2011.
Our sources tell us Sting may make his official announcement next month at the WWE Hall of Fame ceremony in Texas ... but we're told it's a done deal.
As far as Sting's future -- it's up in the air. We're told Sting is open to a non-physical role with the company ... but we're told no formal offer has been made.
Sting was a legend in the ring ... rising to superstardom in the late '80s before becoming the face of the WCW and a huge fan favorite in the WWE.