Barcelona on Wednesday confirmed that one player has tested positive for coronavirus ahead of the pre-season return.
The club has also confirmed that the player has not been in contact with any of the squad that are competing in the Champions League.
"Following PCR tests conducted this Tuesday afternoon on the group of nine players due to begin the preseason today, one of them has tested positive for COVID-19. The player has no symptoms, is in good health and has been quarantined at his home," the club said in a statement.
"The club has reported the matter to the relevant sporting and health authorities. All persons who have been in contact with the player have been tracked to perform the corresponding PCR tests. The player has not been in contact with any of the senior team players who are scheduled to travel to Lisbon this Thursday to compete in the Champions League," it added.
Nine players, who had returned to pre-season training, include Pedri, Trincao, Matheus Fernandes, Jean-Clair Todibo, Moussa Wague, Carles Alena, Rafinha, Juan Miranda and Oriol Busquets.
The 22-man squad will travel to Lisbon on Thursday as the Champions League reaches its conclusion in a revised straight knockout format in Portugal.
Barcelona will take on Bayern Munich in the quarterfinal of Champions League on Saturday, August 15.