James McFadden and other key international performers could be left out of Scotland's qualifying campaign to reach the 2010 World Cup if they do not play in the friendly against Northern Ireland in August.

James McFadden and other key international performers could be left out of Scotland's qualifying campaign to reach the 2010 World Cup if they do not play in the friendly against Northern Ireland in August.

George Burley, the national team manager, said yesterday that players who do not make themselves available for warm-up games risk being overlooked when Scotland return to competitive action against Macedonia in September.

Burley suffered seven call-offs ahead of his debut match against Croatia at Hampden in March and will be without four of his original selection for Friday's friendly with the Czech Republic.

McFadden is the only player to withdraw from both of the squads although several Rangers players were excused duty on this occasion due to their recent fixture overload. Burley said those who travelled with him to Prague this week would be in pole position' when it comes to selection for the World Cup campaign.

"These matches are all very important because it's the build-up for the World Cup," the national coach said. "If you don't have proper preparation, it's difficult, and that's something we'll look at.

"The players who are playing have more advantage of being in the team than the ones who are not. They are in pole position and, naturally, if they perform well they've got a very good chance of staying in the side.

"You can say that we might not have the best team together until the first World Cup qualifier. But how do you say what is my best team? The only best team I can see is the one I've got playing for me at the moment."