Alex Sanderson is to take up a coaching job at Saracens after deciding to quit professional rugby due to injury.
Alex Sanderson join Sarries from Sale in 2004
The 26-year-old back row forward has missed much of last two campaigns.
Sanderson returned to action this season and made six appearances, but has decided to retire on medical advice because of a long-term back problem.
"It's a massive disappointment but this is something that's been with me for the last 20 months so I always knew the end was around the corner," he said.
"I'd just hoped it wasn't going to be so soon. It's a chronic problem that isn't going to get better, but when you have to make the decision, it still comes as a shock.
"There is no short-term solution and the longer I play the more chance there is of causing permanent damage. Even now I realise that I will still have to have more surgery at some point."
Sanderson will join the Sarries coaching staff, concentrating on contact skills and working with the squad on other areas of the game such as rucking and mauling.
Director of rugby Steve Diamond, who coached Sanderson at Sale, said: "It's very disappointing news that Alex has been forced to retire.
"But he is getting on with his life, and an opportunity has arisen for him to work alongside myself and (head coach) Mike Ford.
I've known Alex since he was 15 and the value he can bring to an organisation. We've lost a player but gained an asset in another area."