Blackburn defender Grant Hanley has pulled out of the Scotland squad to face Wales and Belgium with a groin injury.
And Norwich winger Robert Snodgrass is doubtful for the World Cup qualifying double header after being hit by an ankle problem.
Scotland assistant manager Peter Houston confirmed Hanley's withdrawal after the first training session at their Mar Hall base ahead of Friday's game in Cardiff.
Houston said: "Grant Hanley has a groin strain and he is going to miss out."
- Grant Hanley