Astori passed away during his sleep the night before Fiorentina were due to play Udinese.
All Serie A fixtures have now been postponed though as Italy mourn the loss of the 31-year-old central defender.
Fiorentina captian Astori joined the club in 2016 but previously played for Milan, Roma and Cagliari.
He also earned 14 international caps for Italy before his life was tragically cut short.
A report from Italy said worry began when Astori failed to come down for breakfast or answer his phone, with team-mates forced to break down his door.
'The lad did not turn up to the team breakfast at 9.30am and he was usually the first to arrive,' said Fiorentina spokesman Arturo Mastronardi.
'So they went to check on him. Davide was sleeping in a room on his own. We still don't know the cause of death. The Magistrate came here and the body has been taken for an autopsy, which I think will be conducted today. We have no further details.'
Astori leaves behind wife Francesca and a two-year-old daughter.