The Turin club, whose under-23 team play in Serie C, said it was a precautionary measure and they were in constant contact with health authorities.
“It is specified that, six days after the game, the Juventus players remain asymptomatic and are under medical supervision,” added the club statement.
Gazetta dello Sport said the players had been quarantined in their homes, though this was not mentioned by Juventus.
Their under-23 side beat Pianese 1-0 last Sunday.
Earlier, Pianese said that “after a series of checks, Pianese announce that a fourth player is infected by Covid-19.
“He too is in solitary confinement at home and is under observation by the relevant authorities.”
One member of staff has also been infected.
The club, based in Piancastagnaio in the region of Tuscany, said on Friday that the entire squad have been quarantined in their homes.
It said the first player tested positive on Thursday, several days after he missed a match because he was feeling slightly feverish.
The number of deaths in Italy from the illness rose to 29 on Saturday and the accumulated total of cases reached 1,128, authorities said.
Twenty of the 30 Serie C matches this weekend have been postponed because of the virus. Five Serie A games have also been called off.(Reuters/NAN)