Even as Portugal clubs began training last week and players found COVID-19 positive, the Portuguese government has issued guidelines for restart of the Primeira Liga.
Portugal, preparing to restart its professional soccer league on May 30, will not automatically order entire squads to be quarantined if one or more players test positive for coronavirus.
Government health guidelines, published by the Portuguese Football Federation (FPF), said players should remain at home in a form of self-isolation, except to go to training and matches, and must be tested twice in the 48 hours before a game.
Portugal's Primeira Liga teams began training last week ahead of the planned re-start. Vitoria Guimaraes said on Sunday three players had tested positive and been isolated while the rest of the squad would continue with individual training.
On Monday, Portugal's reigning champions Benfica have confirmed that midfielder David Tavares tested positive for coronavirus on Friday, taking the tally for positive cases to at least eight players in Primeira Liga.
21-year-old Tavares, who is not a regular first-team player, was asymptomatic and in quarantine. His positive test comes after Vitoria Guimaraes confirmed three positive cases on Saturday and Moreirense one more.
AFP reported that, according to the Portugese news agency Lusa, three Famalicao players are also infected, as well as two members of the club's non-playing staff.
When Primeira was suspended on March 12 due to the coronavirus pandemic, Porto were top of the table with a one-point lead over Benfica.
Portugal's guidelines state that players testing positive must be isolated but that the implementation of regular testing should mean collective quarantine is not necessary.
"The implementation of the containment and testing measures indicated in this protocol minimises the risk of contagion among the athletes and other squad members, so the identification of a positive case does not in itself make collective isolation of the teams mandatory," the government document said, adding that the local health authority was ultimately responsible for a decision.
Players, coaching staff and referees must remain at home until the end of the season, except for matches and training.
"Movements should be restricted to the home-club/competition-home route. Only social contacts with cohabitants and club members are permitted," the document said
Before competition re-starts, players, coaches and officials should undergo two tests 14 days apart. Once competition gets under way, all those involved must undergo a test 48 hours before the match and another one as close as possible to the start of the game.
The document also said competition should take place in the minimum possible number of stadiums.
Domestic leagues around Europe are attempting to return to action following the coronavirus stoppage, with the Bundesliga to start on May 16, but the question of how to deal with a positive case within a squad is proving a difficult issue.
The entire squad of German second division side Dynamo Dresden were ordered into quarantine on Saturday for 14 days by local authorities after two players tested positive. German law states that any response to cases is a matter for the local health authority.
Attempts to restart the league in Austria have floundered on a government requirement that entire squads must be quarantined in the case of a single positive test.