He was one of nine reporting for pre-season training, showed no symptoms and has been quarantined at his home.
Barcelona say he has not been in contact with any senior players, who travel to Lisbon on Thursday
Valencia confirmed two cases of coronavirus this week, while Atletico Madrid reported two positive tests.
Because of the COVID-19 pandemic, the Champions League is concluding with a ‘final eight’ tournament in Lisbon, comprising single-leg games held behind closed doors.
Barca play Bayern on Friday, the day after Atletico Madrid face R`B Leipzig.
Everyone who been in contact with the Barca player has been tracked to perform tests.