McArthur has scored four goals in 32 Scotland appearancesScotland v Belgium & Scotland v AlbaniaVenue: Hampden Park Dates: Friday, 7 September & Monday, 10 September (both 19:45 BST) Coverage: Follow live radio and text commentary on BBC Radio Scotland, the BBC Sport Scotland website and mobile app
Crystal Palace midfielder James McArthur has made himself unavailable for Scotland until the new year as he attempts to manage a back injury.
The 30-year-old will not be in the squad named on Monday for the friendly against Belgium on 7 September and the Nations League opener with Albania three days later.
However, Hearts defender John Souttar is set to be selected by Alex McLeish.
He will replace Aberdeen's Scott McKenna, who has a hamstring injury.
The 21-year-old received his first call-up for the summer matches against Peru and Mexico, but had to withdraw with a knee problem.
McArthur, meanwhile, has played in Palace's first three Premier League matches, but believes he needs to spend the next few international breaks trying to rid himself of a niggling back issue.
The former Hamilton Academical player has spoken to McLeish and reiterated his commitment to the national team - something that the manager has accepted.
Source: bbc.com