Gennaro Gattuso's side have still not left for Turin as the 1845 GMT kick-off for the match at Juve's Allianz Stadium approaches.
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.
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)."
Club president Aurelio De Laurentiis, who recovered from coronavirus last month, believes it is "too dangerous" to travel to Turin, and asked on Sunday evening that the match be postponed "without further delay".
Zielinski and Elma's positive tests came after last weekend's a 6-0 thumping of Genoa, who have since recorded 22 positive cases that includes 17 players.
On Sunday, 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, which has two positive players for Covid-19".
'13 healthy players'
Juventus confirmed they would "take to the field" as scheduled despite two positive tests among their staff, with coach Andrea Pirlo naming his match-day squad.
If Napoli, who had won both their Serie A matches so far this season, do not play they would likely forfeit the game 3-0.
Juventus have four points after two games.
Serie A pointed out that other matches had gone ahead despite positive cases such as the game between Torino and Atalanta, AC Milan against Crotone and Napoli's hammering of Genoa.
The league said it had "a precise rule to be adopted in the event of multiple positives that can lead to the postponement of matches only upon the occurrence of certain conditions which, at the moment, do not apply to the case of Napoli."
Serie A are applying UEFA rules that say a match can take place as long as a side have 13 healthy players, including a goalkeeper.
The only possible exemption would be a club which has an active outbreak of Covid-19 with more than 10 new positive cases in a week.
In that case the club can request a postponement, but only once in the season, which was the case of Genoa's game this weekend against Torino.
Serie A insisted "that the system of rules in force must guarantee maximum health protection for the people involved, equal treatment between the various clubs, as well as respect for the principles of fair play."
But Napoli believe the health instructions of their regional authorities are contradictory to Italy's sports health protocol, in a standoff which could have major consequences for the rest of the season.
The players may have to remain in self-isolation for two weeks at a hotel near the club's facilities, Italian media said on Sunday.
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