Wigan midfielder James McArthur has been called into the Scotland squad for Wednesday's friendly against Slovenia after Celtic captain Scott Brown pulled out with a groin injury.
Blackpool winger Matt Phillips and Sunderland full-back Phil Bardsley are both doubtful for the trip.
Phillips has arrived at the Scotland camp to have his hamstring injury assessed, the Scottish Football Association confirmed on their Twitter account.
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, had been expected to drop out after suffering a hamstring injury as Blackpool lost to West Ham in 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 on Saturday.
Blackpool manager Ian Holloway previously stated he did not want the 20-year-old, who won his first call-up after his family informed the Scotland set-up of his eligibility, to travel to Slovenia as Blackpool face Hull in the npower Championship on Friday.
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.