The party in question was held by the United States international and attended by his two team-mates as well as between 10 and 20 other individuals.
They will all face sanctions from the local authorities and a fine from Juventus, but the club are believed to be furious at the breach and could use make an example of the trio by suspending them for a few matches.
If that happens, they will miss this weekend's Turin derby against Torino.
Arthur would have missed the game anyway, as he is injured.
The coronavirus has hurt the Bianconeri in other areas, too, as defenders Leonardo Bonucci and Merih Demiral have tested positive, meaning they will now have to self-isolate.
Furthermore, they are missing Giorgio Chiellini too after he picked up a knock on international duty.
That could mean a place at centre-back for Danilo alongside Matthijs de Ligt in what will be a patched-up defensive line in the derby.
Expect Juan Cuadrado to play at right-back, with Alex Sandro at left-back.
With Arthur and McKennie both out, that could present an opportunity for Aaron Ramsey to start either on the left or right of the midfield four, with Federico Chiesa on the opposite flank and Rodrigo Bentancur and Adrien Rabiot in the middle.
Alvaro Morata might be selected ahead of Dejan Kulusevski to partner Cristiano Ronaldo.