Scotland fly-half Finn Russell will miss the Six Nations opener against Ireland after a "breach of team protocol", Scottish Rugby said on Thursday.
The Racing 92 stand-off will not play in Scotland's opener against Ireland on February 1 and it is unclear whether he will play at all in the campaign.
"Stand-off Finn Russell will play no further part in preparations for Scotland's Six Nations opener against Ireland, having been disciplined for a breach of team protocol during the week's camp in Edinburgh. He has returned to his club," a Scotland team spokesman said in a statement.
The 27-year-old, who made his debut for Scotland in 2014, has emerged as a key figure in Gregor Townsend's side.
His potential absence for the entire Six Nations would be a huge blow for Scotland as they look to bounce back from a disappointing World Cup campaign last year.
The in-form Adam Hastings is now almost certain to wear the number 10 jersey in Dublin but Townsend may look for reinforcements with no other regular stand-offs in his squad.
Full-back Stuart Hogg did play there earlier in his career and Northampton centre Rory Hutchinson can also fill the position.
Glasgow's Pete Horne was a notable omission from the original squad, while Duncan Weir is playing regularly for Worcester, having not represented his country since 2017.
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