Rangers duo Kevin Thomson and Steven Whittaker have pulled out of Scotland's squad to play Wales in a friendly on Saturday.
Whittaker injured his hamstring in Gers' weekend win over St Mirren while Thomson has failed to recover from a sickness bug.
Scotland head coach George Burley had hoped to have the pair available and has now called up Blackpool's Charlie Adam as a replacement.
"Kevin is still laid low with a virus after one or two of the Rangers players were affected after their European game," explained Burley.
"The doctor looked at him this morning and he is still not 100 per cent. We were hoping to take him with us tomorrow but unfortunately he is still laid low.
"Steven Whittaker has a hamstring injury and will not be available either.
"We have called Charlie Adam into the squad who did very well at the weekend and scored a cracking goal for Blackpool.
"He is a very good replacement, he has been playing very consistently, he is a quality player and he is getting a real benefit from playing regularly."
Burley will also continue to monitor the fitness of captain Darren Fletcher, who has been troubled with an ankle problem recently.
He continued: "We will train tomorrow and see how everyone is. It's nice to get the squad back together again and this is a game we are all looking forward to."