The cases were confirmed amid a screening test on Friday of all the club's staff, coaches and players.
Three players from Portuguese top-flight club Vitoria Guimaraes have tested positive for COVID-19.
The players are "asymptomatic and quarantined," the club said in a statement on Saturday night, without naming them, reports Xinhua news agency.
The cases were confirmed amid a screening test on Friday of all the club's staff, coaches and players.
The Portuguese government announced on April 30 that the Portuguese first division would be allowed to resume from the last weekend in May, behind closed doors and subject to the approval of a health protocol.
Sports and health authorities are still working on this protocol and have not yet confirmed the date for the resumption of matches, with ten rounds still to be played.
Teams in Portugal's top division have resumed individual training to prepare for the resumption of the season, scheduled for the end of May.
At least one other player had already tested positive last week, from the under-23s of the Lisbon club Belenenses.
Meanwhile, five players have tested positive for coronavirus across Spain's top two divisions, LaLiga said in a statement on Sunday.
"After carrying out the mandatory medical tests among essential staff at LaLiga clubs in order to resume training, a number of positive COVID-19 cases have been detected," the statement read.
It added that all players are asymptomatic and in the latter stages of the deadly virus which has gripped the world.
