Fiorentina captain and Italy international Davide Astori passed away overnight on Saturday in the hotel where he was with staying his team.
Astori, 31, was with his teammates when he died in his sleep ahead of Sunday night's Serie A game against Udinese.
That game has subsequently been postponed and Fiorentina issued a short statement calling for respect at this difficult time for the club and the defender's family.
Serie A has subsequently confirmed that all Sunday's top flight games in the country have been called off.
“Fiorentina are profoundly shaken and forced to announce that their captain Davide Astori has died,” the Italian side said.
“For this terrible and delicate situation, and above all out of respect for his family, we appeal to the sensitivity of the media.”
Astori came through the youth academy at Milan and went on to play for Pizzighettone, Cremonese, Cagliari and Roma before initially joining Fiorentina on loan in 2015.
He joined the Viola on a permanent basis in 2016 and earned 14 Italy caps throughout his career.