Serie A club Roma postponed the club's return to training for the new season on Friday after four players tested positive for coronavirus.
After goalkeeper Antonio Mirante announced he was positive last week, Spanish striker Carles Perez on Thursday confirmed he also had COVID-19.
On Friday, Brazilian left-back Bruno Peres said on Instagram that he too was "unfortunately positive" but without symptoms.
"I will respect the days of isolation but I can't wait to get back to work with the rest of the team," Peres wrote with the Italian league set to resume on September 19.
Dutch forward Justin Kluivert was the fourth player to test positive, according to Sky Sport Italia and Gazzetta Dello Sport.
The 21-year-old Kluivert had just returned after holidays in the Netherlands and the Spanish island of Ibiza.
Roma's return to training has been pushed back 24 hours, with new tests on players on Saturday, according to media reports.
Other Italian teams have also reported positive cases as players and staff return from holidays.
Bologna coach Sinisa Mihajlovic, who has undergoing treatment for leukaemia since last year, tested positive for COVID-19 and is in isolation.
Sardinian club Cagliari have registered four positive players -- Filip Bradaric, Luca Ceppitelli, Alberto Cerri and Kiril Despodov.
Sassuolo announced the positive case of striker Jeremie Boga. Napoli striker Andrea Petagna has also tested for the virus.
Torino announced two cases, without revealing the names, as did promoted Benevento.