Italy international Davide Astori, capped 14 times by his country, has passed away on Sunday.
The 31-year-old centre-back had been had enjoyed a professional career spanning 12 years.
Astori and his team-mates were preparing to face Udinese in a Serie A fixture on Sunday before Fiorentina announced the tragic news ahead of the game, which has now been cancelled.
"Fiorentina are profoundly shaken and forced to announce that their captain Davide Astori has died," a statement posted on the club's official website reads.
"For this terrible and delicate situation, and above all out of respect for his family, we appeal to the sensitivity of the media."
Astori started out at AC Milan, where he never played a Serie A match, before moving to Cagliari, the club where he made his big breakthrough, reports Goal.com.
He turned out 174 times for the Sardinians in a six-year spell, during which he made his national team debut with the Azzurri.
In 2014, he was sent on loan to Roma and then a year later made a similar transfer to Fiorentina, but with an obligation to buy at the end of the season.
Astori had established himself as a vital member of the squad and had turned out 27 times for the side ranked 10th in the Serie A standings this term.
The news has been met with huge shock and messages of condolences from the football world , with clubs and players from across the globe sending words of support to Astori's family.
It has also been confirmed that, as well as the Udinese vs Fiorentina game, the remaining six Serie A matches due to be played on Sunday have been cancelled as a mark of respect following Astori's death.