Astori's number 13 shirt retired by Fiorentina and Cagliari following tragic passing

The Serie A side will pay tribute to the captain following his death earlier this month and have promised more plans to honour him

Fiorentina and Cagliari have announced that they will be retiring their No. 13 shirts in the wake of Davide Astori’s tragic death.

It was confirmed on Sunday morning that the 31-year-old Viola captain had passed away in his sleep, with tributes having flooded in from across the football world.

Former clubs, fellow professionals and a number of sporting organisations have been quick to pass on their condolences to the Astori family and those who knew him best.

Fiorentina and Cagliari – two sides that the defender represented with distinction over the course of his career - have now revealed that as a mark of respect, they will no longer be bestowing Astori’s squad number on any other player.

A statement from the Florence-based club read: “To honour his memory and make the memory of Davide Astori indelible, Cagliari and Fiorentina have decided to jointly withdraw the shirt with the number 13.”

Cagliari posted a similar message on their social media channels.

Manslaughter proceedings have been opened by Italian authorities as they seek to determine the cause of Astori’s sudden death, with Udine chief prosecutor Antonio De Nicolo having made that announcement to Radio Rai on Monday.

He said: “We have opened criminal proceedings over the hypothesis of manslaughter.

“For now, it’s been brought against unknown persons. We’ve arranged an autopsy, which will be performed soon.”

Under Italian law, the only way an autopsy could take place on Astori in order to discover the cause of death was to open such a case.

As such, there is currently no suggestion of foul play involved in the passing of the former AC Milan youth player, who subsequently starred at the likes of Cagliari and Roma before moving to Fiorentina.

De Nicolo later clarified to ANSA: "We have a duty to ascertain whether Astori’s death was a tragic fatality of if someone knew something.

"For now, no-one is responsible, neither is there anyone who seems as if they could answer anything.

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"The start of this judicial procedure allows us to identify any responsibility on the part of anyone."

It has also been revealed by UEFA that a minute’s silence will be observed ahead of all Champions League and Europa League fixtures due to be staged at the round of 16 in the respective competitions.