Celtic and Scotland midfielder Scott Brown has been ruled out for at least six weeks with a metatarsal injury.
Brown was forced to withdraw from Craig Levein's squad ahead of Friday's Euro 2012 qualifier against Czech Republic in Prague after a decision was taken not to risk aggravating what was described as an ankle problem.
It was assumed Brown would return to the Scotland camp on Saturday to be assessed ahead of next Tuesday's clash with Spain at Hampden.
However, Celtic's medical staff have investigated the problem and a statement on the club's website read: "Following scans it has been found that Scott has suffered a stress reaction in the third metatarsal on his right foot.
"Investigations are ongoing but it is likely that Scott will, unfortunately, be out for a period of six weeks.
"However, this could potentially be longer, though the club will only know after Scott sees a specialist next Tuesday."