Three Fiorentina players and three members of the club's support team tested positive for the coronavirus.
Serie A clubs have received permission from the Italian government to resume training, although players can only train individually.
The players and the team have been isolated and the rest of the group will undergo medical and fitness tests.
A Torino player also tested positive for the virus on Wednesday and was quarantined.
No club named the players who tested positive.
Italy began to ease its restrictions after an eight-week blockade.
Serie A clubs have returned to training, but there has been no decision on when the league will resume.
In a statement, Fiorentina stated: "The club has, according to the protocol, started to isolate those involved.
"The rest of the group is scheduled to undergo medical and fitness tests before the optional field activity begins."