Cristiano Ronaldo, 35, will isolate himself from teammates. Another round of testing revealed he was the only player on the team to test positive.
The federation said he "is doing well, without symptoms, and in isolation."
Ronaldo, a forward for the Italian club Juventus and the Portugal national team, played in a friendly match against Spain last week and in the Nations League match against France on Sunday. Neither of the other two teams have reported positive cases.
On Monday, Cristiano Ronaldo posted a photo of himself on social media dining with his teammates.
"United on and off the field," he wrote.
Two other Portugal players, Jose Fonte and Anthony Lopes, tested positive last week, according to ESPN. Earlier this year, three Juventus players — Daniele Rugani, Blaise Matuidi and Paulo Dybala — and the team doctor contracted the coronavirus, according to The Associated Press.
And earlier this month, two staff members contracted the virus, forcing the team to quarantine.
Cristiano Ronaldo will sit out Portugal's UEFA Nations League game against Sweden on Wednesday. The match has not been postponed.
The coach of the Juventus FC under 23 reserve team, Lamberto Zauli, also tested positive for the coronavirus, the club said Tuesday. The reserve team has entered into isolation as a result.
"The club is in constant contact with the competent health authorities," the statement read.
Cases on other teams
Cristiano Ronaldo isn't the only soccer star who recently tested positive.
Manchester United midfielder Paul Pogba was found to be positive. Brazilian star Neymar and two of his Paris Saint-Germain teammates reportedly contracted the virus during a postseason vacation.
On Monday, Peru's soccer federation said two of its players won't play in a qualifier against Brazil on Tuesday night after testing positive.
The Premier League recently reported five new positive cases after testing 1,128 players and club staff.
The United States' highest level soccer league, Major League Soccer, postponed the next three Colorado Rapids games following an outbreak of cases on the team. The league already rescheduled four previous Rapids matches since Sept. 26.
Five Rapids players and 12 staff members tested positive between Sept. 24 and Oct. 9.
The team has not reported any new cases since then.
The league said the decision to postpone games was made "based on the total number of current cases and in consultation with the Colorado Department of Public Health and Environment."