Sheffield United midfielder John Fleck has tested positive for Covid-19 while in Spain with the rest of the Scotland squad ahead of the Euros.
The Sheffield United player has been ruled out of Wednesday’s friendly against Holland in Portugal.
Fleck will now follow Spanish coronavirus rules and self-isolate at the Scots’ training base in La Finca.
An SFA spokesman added: “The rest of the squad was re-tested for Covid-19 and returned negative results today.”
Scotland are in Spain for the first part of their build-up to Euro 2020 – their first major tournament in 23 years.
Clarke’s side face Czech Republic, England and Croatia in their three group games but before that they will take on Holland and then have a friendly away to Luxembourg on June 6.