Alan Hutton has become the latest player to withdraw from the Scotland squad through injury.
The Aston Villa full-back has been unable to shake off a hamstring injury in time for the match against Slovenia.
He has joined Scott Brown, Matt Phillips and Phil Bardsley, who pulled out of Craig Levein's squad yesterday.
Levein has reacted by handing a first call-up to Bristol City defender Richard Foster.
The former Aberdeen full-back is expected to compete with Russell Martin for a starting role.