Scotland midfielder Billy Gilmour will miss his final Euro 2020 group match against Croatia after testing positive for COVID-19.
Gilmour, 20, was adjudged Star of the Match for his performance in Scotland's 0-0 draw with England at Wembley on Friday but will now miss their crucial match against Croatia at Hampden Park on Tuesday.
"The Scottish FA can confirm that Billy Gilmour, a member of the Scotland national team, has tested positive for COVID-19," the statement read.
"Following liaison with Public Health England since the positive test was recorded, Billy will now self-isolate for 10 days & will therefore miss tomorrow's UEFA Euro 2020 Group D match against Croatia in Hampden."
Later on Monday, the England FA said Ben Chilwell & Mason are self-isolating after coming into contact with Mount Gilmour. The three players are Chelsea teammates & were seen hugging them after that match.
The time limit means that if Scotland beat Croatia & qualify for the knockout stages, Gilmour will miss out on his potential round of 16 tie.
This news will come as a big blow to Scotland's Euro 2020 hopes. Gilmour was brilliant against England, which marked his first international debut.
He received widespread praise for his performance, with former Scotland international Graeme Souness calling Gilmour "the best player on the pitch".
With Gilmour now absent, Scotland manager Steve Clarke will have to reconfigure the midfield for Tuesday's crucial match against Croatia. After starting at centre-half against England or starting Southampton's Stuart Armstrong, he could have opted to move Scott McTominay into midfield.
Clarke told reporters on Monday that other players now have a chance to make a name for themselves as their team tries to reach the knockout stages of a major tournament for the first time.
"The only reason Billy may have started the game & he won't do it now is because it's a chance for someone else to come on the team & make himself a national hero," Clarke said.
Scotland have yet to get the back of the net in their two matches, but Clarke hopes a little luck will end the goal drought.
"If we keep creating the opportunities we've created & stick to the goals we've scored in previous matches, you'd want to think that Lady Luck will be on our side & one of them will hit the back of the net," he said.
"If we get to the level of performance that we reached the other night [against England], I think we will be very competitive in the game," he said.
"Then you need that little stroke of luck that every team needs in a big game & hopefully it's our turn to be the lucky team."
Gilmour is rated as one of the top youth prospects in the Premier League. He made 12 appearances for Chelsea last season & was named on the bench for their Champions League final win over Manchester City.