According to the statement, Ronaldo is “well, without symptoms, and in isolation.”
The 35-year-old Juventus forward played for Portugal against France in the Nations League on Sunday and against Spain in a friendly last week.
Ronaldo will now miss his country’s next Nations League fixture against Sweden on Wednesday, as well as Juventus’ upcoming matches which include a Serie A clash with Crotone and a Champions League group game against Dynamo Kyiv.
Despite surging cases of Covid-19 across the globe, many footballers have left their clubs to play international games.
However, some clubs have not released players to play for their countries, including Austrian side RB Salzburg whose players were called up for Mali, Cameroon, Zambia, Austria and Hungary.
The forward has scored three league goals in two games for Juventus so far this season — one against Sampdoria and a brace against AS Roma.
He also scored twice as Portugal defeated Sweden 2-0 in the Nations League last month.
He then helped Juventus lift the Serie A title following the league’s resumption.