Stephen McManus has become the latest player to be ruled out of Scotland's World Cup qualifier against Holland on Saturday.
Scotland boss George Burley has been hit with a number of withdrawals for the crucial clash in Amsterdam, with a home meeting against Iceland to follow on Wednesday.
McManus becomes the fifth player ruled out of the Holland game after Paul Hartley, David Weir, Kirk Broadfoot and Kris Commons all pulled out of the squad.
But the Celtic defender could still feature against Iceland, although he has not travelled with the Scots party to Holland due to his ankle problem.
Scotland coach Steven Pressley said: "Stephen McManus will not be involved this weekend. He did some light running today and was still feeling his ankle."
McManus will receive treatment from Celtic in a bid to return to fitness before the World Cup qualifier against Iceland at Hampden next Wednesday.
Pressley said: "We will assess him over the next three or four days and we are hopeful he might be available on Wednesday."
There was better news over captain Barry Ferguson, who has not trained with the rest of the squad after picking up a chest injury.
Pressley said: "Barry Ferguson came through the late running OK and we are confident that he should make Saturday's game."
The injury to Celtic skipper McManus means Wolves defender Christophe Berra is likely to partner Gary Caldwell in central defence, with Falkirk's Darren Barr also hoping for a start.