Striker Che Adams and midfielder John McGinn are among the seven players Scotland will be without for Wednesday's friendly
A further six Scotland players will miss Wednesday's friendly against the Netherlands due to Covid-19 fears following John Fleck's positive test.
David Marshall, Stephen O'Donnell, Nathan Patterson, Grant Hanley, John McGinn and Che Adams have not travelled with the squad to Portugal.
They have all tested negative but have been kept back as a precaution.
Fleck is self-isolating at Scotland's training camp in Alicante having tested positive on Tuesday.
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The 29-year-old midfielder is asymptomatic but has to quarantine for 10 days – or until he records two negative tests – in accordance with Spanish health protocols.
It leaves manager Steve Clarke with just 19 players for the first of two Euro 2020 warm-up games.
Scotland face Luxembourg on Sunday before beginning their Group D campaign eight days later against the Czech Republic at Hampden.
Clarke, speaking on Tuesday, was hopeful of avoiding further Covid scares following Fleck's result.
"For everyone else, it's just carry on as normal and continue the good work," he said.
"The thing I don't want is for this isolated case to overshadow the good work that we've done.
"We'll have to be reactive to certain situations but there's no point stressing about it. There are certain situations that you can't control."