Juventus forward Paulo Dybala on Thursday apologised for breaking Covid-19 rules by attending a house party with teammates Weston McKennie and Arthur Melo.
The Juventus trio were reported to have been fined by police who were called by neighbours to the lockdown get-together at US midfielder McKennie's Turin home.
"I know that in such a difficult time for the world with COVID it would have been better not to make a mistake, but I was wrong to stay out for dinner," Argentine forward Dybala wrote in a post on Instagram.
"It wasn't a party, but I made a mistake anyway and I apologise."
The three players, who all missed international call-ups with injuries, could also face club sanctions but no decision had yet been made on the matter, a club source said.
The Italian champions have had new coronavirus positives this week after the return of their international players.
Centre-back Leonardo Bonucci tested positive on Thursday after returning from Italy duty.
"Bonucci underwent a test for Covid-19 which came back positive," Juventus said in a statement.
"The player has already been placed in home isolation."
Turkey defender Merih Demiral also tested positive while with his national side and returned to Turin on a medical flight, the team said.
The 23-year-old is isolating in the Juventus team's J-Hotel.
Both players will miss Saturday's Turin derby against Torino.
Four members of Italy's staff contracted the virus during the team's World Cup qualifiers, the Italian Football Federation (FIGC) had announced Wednesday after a 2-0 win in Lithuania.
The Azzurri also played in Bulgaria on Sunday, three days after beating Northern Ireland in Parma, both also with a 2-0 scoreline.
The entire Italy team had been tested in Sofia on Monday, with negative results, but on Tuesday a staff member complained of mild symptoms with a sore throat.
The individual was isolated and returned to Italy where a test was positive, and three other officials tested positive in Vilnius.
Meanwhile, Sassuolo said that their four Italy internationals Gian Marco Ferrari, Manuel Locatelli, Domenico Berardi and Francesco Caputo will not play against Roma "as a precaution" this weekend despite their negative tests.
Sassuolo's Turkish defender Kaan Ayhan contracted the virus with his national side becoming the seventh player at the club infected this season.
Other Italian internationals tested negative on their return home with Napoli confirming Lorenzo Insigne, Alex Meret and Giovanni Di Lorenzo had all been given the all-clear on Thursday.
Milan goalkeeper Gianluigi Donnarumma was also negative.
Inter Milan's three Italy internationals Nicolo Barella, Stefano Sensi and Alessandro Bastoni trained individually on Thursday while awaiting their results.
Bologna's Polish goalkeeper Lukasz Skorupski has also tested positive.