Wales international wing Eli Walker has announced his retirement from rugby at the age of 25.
The prolific Ospreys try-scorer has been unable to make a complete recovery from back surgery early last year.
Walker made one Test match appearance, playing in a 2015 World Cup warm-up match against Ireland, with injury setbacks often stalling his progress.
He played 81 times for the Ospreys, scoring 23 tries, and helped them to the PRO12 title in 2012.
In a statement released by the Ospreys, Walker, who made his decision in consultation with specialists, said: "It is an extremely difficult thing to do, acknowledging and making the decision that you have to retire from the game.
"But it is absolutely the right thing for me to do.
"I've worked hard to try to get back to where I was pre-surgery, but unfortunately, I recognise that I am not going to be able to do so.
"I'm thankful for the support I've had from my family and from the Ospreys during what has been a tough period for me personally.
"I am immensely proud of everything I've achieved on the rugby pitch, be that playing for Swansea, representing my home region, the Ospreys, or gaining my full Wales cap, and without the support of my mother, in particular, I wouldn't have able to achieve anything like I have in my career.
"There are so many fantastic memories that will live with me forever. The sport has allowed me to meet some fantastic people who are now firm friends, and experience some great places. I consider myself fortunate."
Walker, whose blistering pace underpinned his game, made his Ospreys debut as an 18-year-old. He was capped by Wales across all age-grades and was selected in several senior Wales squads.
Ospreys managing director Andrew Millward added: "Everyone is saddened by this news.
"Eli is someone who came through the development system and was identified at a young age as having the potential to become a senior player for the region and for Wales, with his physical attributes and rugby ability marking him out as someone with a bright future.
"He established a reputation as a quality finisher of the highest level and enjoyed many stand-out moments in an Ospreys shirt. His try in the unforgettable win over Toulouse at the Liberty Stadium summing up his ability.
"It is a real shame for Eli, and for the Ospreys, that injury has cut short his career before even reaching what should be his prime.
"However, he should be proud of what he has done in the black shirt and how he has represented himself, his family and the region.
"Always a fans' favourite, he has given us all some special moments to remember and will always be thought of as a true Osprey."