The 31-year old Fiorentina captain was found dead in the team hotel ahead of his squad's Serie A contest against Udinese. The game was postponed until further notice, Sputnik reported.
The precise cause of death has yet to be determined, but the paramedics at the scene opined that it was cardiac arrest.
Astori was just set to sign a new extension with Fiorentina, committing to the club until 2022 before the terrible news broke Sunday afternoon.
The veteran defender joined Fiorentina from Cagliari in 2015, appearing in over 100 matches for the team. The Italian international with 14 caps to his name started out with AC Milan, and enjoyed a 12-year Serie A career.
"Fiorentina are profoundly shocked to have to announce the death of captain Davide Astori after a sudden illness," said a statement on Fiorentina's official Twitter page.