Matt Phillips and Phil Bardsley will not travel with Scotland for the friendly against Slovenia after being ruled unfit.
Blackpool winger Phillips has a hamstring injury while Sunderland full-back Bardsley has a suspected tear in his calf.
The pair join Celtic midfielder Scott Brown in pulling out of the squad. Wigan midfielder James McArthur was added after Brown withdrew last night but no-one else has been called up.
Phillips arrived at the Scotland camp to have his hamstring injury assessed, the
Brown missed Celtic's 1-0 win over Motherwell after going off injured during his side's 2-0 victory over Dunfermline on Wednesday.
Former Hamilton midfielder McArthur played 90 minutes as Wigan drew 0-0 with Aston Villa on Saturday.
Aylesbury-born Phillips, who qualifies for Scotland through his grandfather, has been expected to drop out after suffering a hamstring injury as Blackpool lost to West Ham midweek.
The England Under-20 international, who has registered his change of allegiance with FIFA, missed his side's 3-1 win at Bristol City at the weekend.
Bardsley played 90 minutes as Sunderland lost 4-0 against West Brom on Saturday but the SFA revealed he was doubtful with a calf injury.
Australia defender Rhys Williams is hoping that a positional switch for his club does not damage his bid to lock in a centre-back spot for his country heading into the FIFA 2014 World Cup.