Sunderland goalkeeper Craig Gordon could miss the start of next season after undergoing knee surgery in Sweden on Monday.
Gordon, 28, is expected to be out for up to six months after the procedure, which was carried out by knee specialist Professor Hakan Alfredson.
"We were left with no choice but to go ahead with the surgery," boss Steve Bruce told the club website.
"Craig had the operation yesterday and it went well."
Gordon is likely to miss Scotland's Euro 2012 qualifiers against the Czech Republic on 3 September and Lithuania three days later.
Scotland then travel to Liechtenstein on 8 October and Spain on 11 October.
The news about Gordon provided a double blow for national coach Craig Levein, with midfielder Graham Dorrans now likely to be out of action for the rest of the season.
Dorrans has not played since February following an ankle injury suffered in training with his club, West Brom.
And Baggies assistant manager Michael Appleton admitted on Tuesday that time is running out for Dorrans to be sufficiently match fit to return during the current campaign.
It means that he could join Gordon in missing Scotland's Carling Nations Cup matches against Wales and Northern Ireland in May, while the goalkeeper is almost certain to miss Denmark's visit to Hampden for a 10 August friendly.
However, Levein is hopeful that Gordon will make a quicker than expected return but is confident that Rangers' Allan McGregor will continue to prove an able deputy.
"Our goalkeeping coach, Jim Stewart, has been keeping in regular contact with Craig and, while early reports suggest six months, there is a chance he could be back within four," Levein told the Scottish Football Association website.
"I will stress, though, that if he has not returned to full fitness at his club then we would not take a chance on him for the double header.
"It is important that Sunderland have him back to full fitness and then we will assess his readiness to return to the international fold."
"We are fortunate to have two world-class goalkeepers and I am sure Allan will relish the challenge of Craig coming back fully fit.
"Obviously it is a big blow to Craig at what is the business end of the season, but the knee problem has been troubling him for some time and he hasn't really felt 100%, so it was best that he went ahead with the operation so he can return earlier next season.
"Simon Mignolet has kept his place in the Sunderland team in recent weeks, so Craig probably felt it best to get the operation now so that he can concentrate on next season."
Before picking up the knee injury, Gordon's season had been disrupted by both a broken arm and the form of understudy Simon Mignolet - delaying his first start until November's 1-1 draw with Tottenham Hotspur.
Since then the Scotland international has made only 15 appearances, the last coming in February's corresponding fixture with Spurs, that the Black Cats lost 2-1.
Former boss Roy Keane signed Gordon for a then club record fee of £9m from Heart of Midlothian in August 2007.