Colorado general manager Joe Sakic said Tuesday that MacKinnon's positive test surfaced Monday and that the center is "asymptomatic and feeling good."
MacKinnon did not practice Tuesday. The earliest he could return is Saturday when the Avalanche host the St. Louis Blues.
That's when Avalanche coach Jared Bednar is expected to return to the bench after being placed on the NHL's COVID-19 protocol last week.
Sakic said the team is 100% vaccinated against the coronavirus.
"I think everybody is tired of dealing with it, but it's here and it's the world we live in," Sakic said. "You've just got to deal with that."
"The guys are responsible and careful in everything they do," Sakic said. "But [COVID-19] is out there. Everybody in every sport is going to have to deal with it. It's not going away anytime soon. It doesn't look like, anyways."