Jack Dempsey has agreed a deal to leave Glasgow Warriors to play his club rugby in Japan - plunging his Scotland future into serious doubt.
Dempsey has been a standout performer in Scotland's back row over recent years and was instrumental in the victories over England and France in the Six Nations.
Firmly established as the first-choice No 8, Dempsey would have been one of the players whom Gregor Townsend was looking to build around heading into the World Cup in 18 months' time.
But there is now no guarantee that Dempsey will be available for selection after talks over a new deal with Glasgow broke down.
Talks were understood to be at an advanced stage and Dempsey was keen to stay, but the length of the deal proved to be a sticking point.
Jack Dempsey was in sensational form for Scotland throughout the Six Nations
Daily Mail Sport understands that, whilst he will earn a lucrative salary in Japan, it was the length of the deal - rather than purely money - that influenced his decision.
Either way, questions will be asked of the powerbrokers at Scotstoun and within Scottish Rugby in terms of why they have allowed one of their top assets to leave in such a fashion.
The identity of his new club in Japan has not yet been confirmed but it is understood that he has committed to moving to the Far East and has already agreed terms.
Dempsey, who turns 32 next month, will end his five-year stint with Glasgow and leave at the end of the season in what is another hammer blow to head coach Franco Smith.
He could be available for Scotland's matches in the summer as they begin the new Nations Championship against Argentina, South Africa and Fiji. But his involvement beyond that looks distinctly unclear.
The Japanese season runs from December-May, so his new club would want their marquee signing settled in during a period when Scotland are due to face New Zealand, Australia and Japan in the autumn.
He would then effectively be unavailable for next year's Six Nations unless Scotland were capable of negotiating some kind of release fee with his club.
But Scotland hooker George Turner dropped off the radar for the national team when he went over to play for Kobe Steelers for a year, before returning to the fold when he joined Harlequins.
If Dempsey was to miss out, either in the autumn or on next year's Six Nations, his involvement in the World Cup would then be in major doubt.
It is a hammer blow first and foremost to Glasgow Warriors, the club for whom Dempsey has excelled since joining in 2021.
Making the move from his native Australia, he rapidly established himself as a key player and was pivotal as they won the URC title in 2024 under Smith.
After a cool-off period for the Wallabies, Dempsey became eligible to play for Scotland in 2022 and was capped immediately by Scotland boss Townsend.
His abrasive style of play and powerful ball-carrying have made him an invaluable member of the Scotland squad.
Dempsey looked like his Six Nations might be cut short when a bicep injury in the game against England threatened to rule him out of the championship.
But he returned only a few weeks later to play a starring role in the stunning victory over France on the penultimate weekend.
Speaking at the time of his return, Scotland captain Sione Tuipulotu said: 'It is great to have him back. His personality off the field always makes things interesting around the group. He's one of my best friends in the group.
'Just having him out there, I don't want to underestimate how big of a boost that is for us as a team to have him back on the park.
'He carries a lot of that emotional energy on his shoulders as well. I've been playing rugby with him for a long time now. I trust him with everything. It's massive to have him back in the group.'