There will be fans inside Hampden in June for the European Championships, believes Professor Jason Leitch.
Scotland's national clinical director says Uefa will be more concerned by the escalating Covid-19 cases in France, Belgium and Germany than in Glasgow.
And he stressed that the situation in other countries should act as a warning to people in Scotland to adhere to the current restrictions.
"We have to watch how we behave in order to get those crowds," he said.
Hampden is due to host Scotland's games against Czech Republic and Croatia, as well as the meeting of those group rivals and a last 16 tie.
Currently, no fans are permitted in Scottish stadiums.
"I think with a fair wind - with good restrictions now - if people follow them, we will have crowds in Hampden and other UK stadia in June," Leitch told BBC Scotland's The Seven.
"I'm not sure that will look normal, I think it may well be limited and distanced.
"I actually think Uefa will be more worried now about France, Belgium, Germany, some other countries where their virus is accelerating rather than decelerating, and that should be a warning to all of us."
The unpredictability of the virus means the relevant authorities have to draft up plans for a range of outcomes, with the tournament now just over two months away.
And Leitch believes a best-case scenario could potentially see over half of Hampden's 51,000 capacity in attendance.
"There are a number of scenarios Uefa, the SFA and the government are working on," Leitch tells BBC Scotland's Off The Ball.
"There are a variety of scenarios from basically zero to half the crowd, or even more than that. I think the most likely is somewhere between those two extremes by the time we get to June."