Glasgow Warriors scrum-half Mike Blair has retired with immediate effect and will take up a new coaching role at the club next season.
The 35-year-old will remain with Scottish Rugby as an assistant coach at the Warriors.
Blair joined Glasgow this season and has made 12 appearances for the club and was voted Player of the Month in October.
The 85-capped former Scotland international has had an illustrious career, representing Edinburgh, Brive, Newcastle Falcons and the Warriors.
Blair enjoyed ten years with Edinburgh, playing his first professional game in 2001. Highlights included being runners-up in the Magners League in 2009 and reaching the semi-finals of the European Cup in 2012.
Scotland's most capped scrum-half captained his country on 14 occasions before retiring from international rugby at the start of 2013, aged 31.
He was named Scotland's Player of the Year in 2008 and was nominated for the IRB World Player of the Year that same season. He toured South Africa with the British and Irish Lions in 2009.
Blair, who is currently sidelined with concussion, made his last appearance for Glasgow Warriors in the win over Cardiff Blues at Scotstoun at the beginning of March.
Speaking to glasgowwarriors.org, Blair said: "It was always my intention to move into a coaching role and although there was an opportunity to play on next year, I believe now is the right time for me to make that change.
"I had originally planned to retire at the end of last season, but I'm glad Gregor (Townsend) persuaded me to play on at Glasgow. I've really enjoyed the season and it's a brilliant environment to be part of.
"With only a few games left this season, I have unfortunately run out of time to be able to regain my fitness before the end of this campaign.
"My recent spell on the sidelines has allowed me to start coaching earlier than expected, working with scrum-halves Henry Pyrgos, Grayson Hart and Ali Price, all of whom are currently playing very well. They have been a pleasure to work with and I look forward to working with them more as the season draws to a close and extending this role to the rest of the squad as we move into next season.
"I'm lucky to have had a long career and to have played with some amazing players and made life-long friends.
"I'll definitely miss the camaraderie on the pitch and in the changing room, but it's time to move on and a new challenge awaits."
Glasgow Warriors head coach Gregor Townsend added: "I was delighted when Mike agreed to come to Glasgow last summer.
"He exceeded our expectations on the field with some outstanding performances and would have been in the running for player of the season before picking up his recent injury.
"In my opinion he is one of Scotland's best ever rugby players and it was great to see him play in a Warriors jersey this season.
"It's disappointing that he's not able to finish his career on his own terms, but he can reflect on a brilliant career both at club and at international level.
"I didn't play with Mike too often but I do wind him up now and again about our first game together as a half-back pairing. It was against USA in the 2003 Rugby World Cup and I ended up getting a bad back picking up some of his passes…it was a wet night so I'll let him off!
"He developed into a very skillful and intelligent player. He always looked to put others into space but also had a very good running game. He became more creative throughout his career in terms of manipulating defences and he was one of the best nines in the game at playing at a high tempo.
"Mike's influence off the field has already had an impact at the club, as our three scrum-halves, Ali Price, Grayson Hart and Henry Pyrgos are all playing well and that is partly down to Mike's coaching and guidance.
"We're looking forward to him joining us in a full-time role as a coach next season. He's helped me with the analysis of opposition and he has some great ideas at improving our attack.
"He'll get lots of opportunities to develop as a coach here and he's excited about that. He'll join our coaching group as an assistant with a primary focus on attack and skills, as well as continuing his work as a scrum-half coach."