The 26-year-old Sale back suffered severe ligament damage during his club’s Heineken Cup victory over Montauban last week.

He has now had an operation, with Sale anticipating a lay-off of up to four months.

Scotland launch their 6 Nations campaign against title holders Wales at Murrayfield on February 8, when Lamont - a full-back or wing - would undoubtedly have been part of coach Frank Hadden’s plans.

Lamont will also sit out the remainder of Sale’s Heineken Cup pool campaign - and possibly the quarter-finals, if Sharks progress that far.

He is a strong contender for the Lions tour to South Africa next summer, although those ambitions have now been dealt a major blow.

Sale rugby director Philippe Saint-Andre said: “This is very bad news for both Sale Sharks and Scotland.

“Rory has been playing well since he returned from his facial injury he sustained in the Calcutta Cup game last season.”