The Serie A season has been postponed since March 9 but moved closer to a resumption this week after the government announced it would permit clubs to resume training on an individual basis on Monday May 11.
However, Fiorentina have now announced that three first-team players and three members of staff have tested positive to COVID-19.
Sampdoria also confirmed that three first-team players from their squad have tested positive for coronavirus, while another player who had already tested positive was still resulting positive for COVID-19.
Both clubs have adhered with protocol around positive tests, sending the players home for isolation.
The situation is an issue for the Italian Football Federation (FIGC) but similar to that which arose in Germany this week yet that didn’t prevent the Bundesliga from confirming plans to resume on May 16.
At least 19 Serie A players had previously tested positive to coronavirus but the latest revelations amid attempts to return to training and competitive matches offers a warning.
The FIGC have said they are determined to complete the 2019-20 Serie A season, which still has 12 rounds of fixtures to play.
Bottom club Brescia, who are based in one of the hardest hit regions Lombardy, have publicly opposed a resumption and haven’t made any plans to return to training.
Meanwhile, Italian Minister for Sport Vincenzo Spadafora said he is “hopeful group training can resume on May 18” having discussed the medical protocol for Serie A clubs with the FIGC and the scientific committee.