Andy Robertson is unlikely to play in Scotland's friendly against Poland at Hampden Park on Thursday.
The Scotland captain missed Liverpool's FA Cup quarter-final at Nottingham Forest due to illness and is still being assessed in Merseyside, while Lyndon Dykes is also a doubt and being monitored by QPR doctors.
Robertson's absence could give 19-year-old Aaron Hickey a chance of making his debut after being called up to the senior squad for the first time.
Craig Halkett and Ross Stewart are also in line for their debuts after being drafted in, with Scott McKenna and David Marshall ruled out - the latter also being replaced by Zander Clark.
Halkett has impressed for Hearts this season in defence as Robbie Neilson's side close in on a third-place finish in the Scottish Premiership.
