Liam Cooper has withdrawn from the Scotland squad after he was injured in Leeds' Sky Bet Championship win over Blackburn on Saturday.
Scotland are already missing Kieran Tierney after Arsenal requested he be left out of the squad - and are likely to be without Scott McTominay - who injured his ankle in Manchester United's win over Brighton on Sunday.
Leeds captain Cooper was substituted after 72 minutes as his side held on for an important 2-1 victory at Elland Road, but scans following the game have shown a small tear in his groin area.
The 28-year-old's injury is not considered to be major with Leeds, who are third in the Championship, hoping Cooper will return after the international break.
Scotland, meanwhile, travel to Cyprus on Saturday and host Kazakhstan on Tuesday - both games live on Sky Sports Football - as Steve Clarke's side look to end Euro 2020 qualifying on a high.
They cannot qualify from Group I but can progress to their first major tournament since 1998 via the Nations League play-offs, which take place in March 2020.
Before that, though, former international Billy Dodds feels it is crucial Scotland avoid defeat to Cyprus and Kazakhstan in their final two qualifiers.
Scotland lost 3-0 to Kazakhstan in the reverse fixture but beat Cyprus 2-1 at Hampden Park in June thanks to Oliver Burke's 89th-minute winner.
"Scotland need belief and momentum," Dodds told Sky Sports. "These play-offs are coming up and you can't look at it any other way.
"We need to try and win these two [European Qualifiers] but just not get beaten - especially in Cyprus. I think we'll take care of Kazakhstan. We're more than capable of winning the two games - but we can't lose."