Napoli failed to turn up for their Serie A clash against Juventus on Sunday after a coronavirus row involving both clubs and health and football authorities.
Gennaro Gattuso's side were not present at Juve's Allianz Stadium for the game's 1845 GMT kick-off.
They were in isolation on the instructions of the regional health authorities of the Campania region which hosts the city of Naples after midfielders Eljif Elmas and Piotr Zielinski both tested positive during the week.
Napoli, who had won both their Serie A matches so far this season, risk forfeiting the game 3-0.
Club president Aurelio De Laurentiis, who recovered from coronavirus last month, said he believes it is "too dangerous" to travel to Turin, and asked on Sunday evening that the match be postponed "without further delay".
Serie A insisted that all the health protocols were in place for the match to safely go ahead as scheduled in Turin.
"The protocol provides ... rules, which allow the playing of league matches even in the event of positive tests, fielding the players who tested negative," the league said in a statement.
It added that these measures are "applicable to the situation of Napoli, who have two positive players for Covid-19".
Napoli are the first team in Europe's five major leagues not to take to the pitch due to the coronavirus pandemic in a game which had remained scheduled.
The club, meanwhile, moved to deny reports that coach Gennaro Gattuso had returned a positive test.
"The news regarding the positivity of Mr. Gattuso for Covid-19 is devoid of any foundation," the club said on Twitter.
"The team group will carry out the next swabs tomorrow (Monday)."
Juventus players arrived at the stadium about an hour before kick-off.