Scotland’s stadiums could be full on 10 August if the Covid route map remains on track, says Professor Jason Leitch.
The national clinical director said the end of social distancing would allow large events such as football and music festivals to resume.
He told BBC Scotland it would be possible given a “fair wind” and if the pace of vaccinations continue.
The first minister has said Scotland is aiming to remove all of its major virus restrictions on 9 August.
Nicola Sturgeon confirmed the date last week as she paused lockdown easing for three weeks to allow more time for people to be vaccinated.
Scotland is set to move to level zero on 19 July with the removal of physical distancing outdoors, but restrictions will remain on events with limits of 2000 fans at football matches.
Prof Leitch told The Sunday Show that the levels system would disappear in August unless there are Covid hotspots or an unexpected slow down in vaccinations.
He said: “On 9 August all physical distancing is removed and the limits on event sizes are removed.
“I would write that in your diary in pencil not Sharpie marker for now.”
Asked if stadiums will be full again on this date, he said: “They can on 10 August but we have had to learn that new word, that ‘indicative’ word.”
Prof Leitch was was also asked if music festivals would also resume. He replied: “Yes, but you are making me sweat just a little.”
The Scottish Premiership season is due to kick-off on 31 July. If the country emerges from level zero on schedule then supporters will only miss the first two round of fixtures.
It would also allow the TNSMT festival on Glasgow Green, which was moved from its traditional July slot, to go ahead from 10-12 September.
The latest Scottish government figures show more than 3.7 million adults have now received their first vaccination while over 2.6 million have had both doses.
A total of 2,639 new Covid cases and one further death, following a positive test, were reported on Sunday.
From Monday, a new online portal will also allow all adults in Scotland who have not received a Covid vaccine to self-register for their first dose.
In order for the timetable to remain on schedule Prof Leitch said hospital figures rather than the soaring case numbers will be critical.
He added: “Previously 1,000 cases would give you 100 people in hospital and 10 deaths in the older waves. That’s tragic numbers, terrible numbers.
“Now 1,000 cases probably gives you about 30 people in hospital and very, very low numbers of deaths.”