Flanker Scott Gray has been ruled out of Scotland's opening matches in the RBS 6 Nations Championship.
The Borders star suffered a knee injury in his club's Celtic League victory over Leinster last weekend.
Scotland doctor James Robson said: "A scan has shown damage to the medial ligaments of Scott's right knee ruling him out of the first part of the Championship.
We will seek further specialist advice in due course to determine just how long Scott may be out for."
The 26-year-old won his first cap against Australia at Murrayfield last year but he will now miss Scotlands opener against France in Paris on Saturday February 5.
The Scots then take on Ireland at Murrayfield a week later and then Italy at the same venue on February 26.
Wales are the visitors to Murrayfield on March 13 before the Six Nations campaign ends against England at Twickenham on March 19.