Shapovalov played last week at the World Tennis Championship exhibition event in Abu Dhabi, where he beat 20-times major winner Rafael Nadal in the third-place playoff match.
Nadal, Olympic champion Belinda Bencic and Tunisian Ons Jabeur all tested positive for the virus after playing the tournament.
Shapovalov said he is experiencing minor symptoms.
“Hi everyone, just wanted to update you that upon my arrival in Sydney, I tested positive for COVID,” Shapovalov tweeted.
— Denis Shapovalov (@denis_shapo) 1640461426000
“I am following all protocols including isolation and letting the people who I’ve been in contact with know. Right now I am experiencing minor symptoms and look forward to getting back on the court when it safe to do so.”
The 2022 ATP Cup will feature 16 teams and be hosted across two venues at the Sydney Olympic Park from January 1-9. Canada are in Group C with Germany, Britain and the United States.
The Australian Open will begin on January 17 in Melbourne.