Ronaldo is feeling well and hasn’t been suffering with symptoms, but is now self-isolating and will play no part in Portugal’s clash with Sweden.
The rest of the Portugal team have returned negative tests and are available for selection.
Portugal’s Football Federation said: “Cristiano Ronaldo was released from the work of the National Team after a positive test for COVID-19, so he will not face Sweden.
“The Portuguese international is doing well, without symptoms, and in isolation.
Ronaldo, 35, played the full 90 minutes of Portugal’s goalless draw with France in Paris on Sunday, having also featured against Spain in Lisbon last Thursday.
He posed for photos with his Portugal teammates at a team dinner on Monday night, as they continued preparations for their clash with the Swedes.
They go into the match top of Group C having won two of their opening fixtures and drawing the other against France.
Sweden have lost all three of their opening matches and are rock bottom without a point