PA Sport understands strikers Kenny Miller (Rangers) and Steven Fletcher (Hibernian) withdrew from the squad last night, joining Manchester United midfielder Darren Fletcher (knee) and Sunderland goalkeeper Craig Gordon (ankle) on the sidelines.

There were also concerns over West Brom midfielder James Morrison and Cardiff striker Ross McCormack.

The likely loss of three of the six forwards named in the original party could prompt Burley to draft in a striker, while he may also elect to bolster his midfield.

The precise details of the injuries to Miller and Steven Fletcher were unknown last night, though both completed a full 90 minutes for their clubs yesterday.

Miller, 28, also withdrew from the squad for last month's World Cup stalemate against Norway, citing a niggling hamstring strain which had dogged him since September's qualifier in Macedonia.

Gordon, who has been manager George Burley's first-choice since he took charge at the start of the year, has not played for his club for almost a month due to a chipped ankle bone.

Morrison limped out of West Brom's 3-0 Barclays Premier League defeat to Chelsea on Saturday with a knee injury shortly before the hour mark.

McCormack has been out of action for Cardiff for a fortnight after sustaining a hamstring problem in a Coca-Cola Championship defeat to Wolves.

He had been expected to return for Saturday's match against Crystal Palace but aggravated the injury in training and did not feature.