Livorno midfielder Piermario Morosini has died after suffering a suspected heart attack during the Serie B match at Pescara on Saturday.
The 25-year-old collapsed suddenly in the first half of the game, leading to the match being abandoned and the remainder of this weekend's games in Italy have subsequently been postponed.
He was treated on the pitch before being taken away by ambulance to the Civile Santo Spirito hospital in Pescara, but he was later pronounced dead.
Morosini had been conscious when put in the ambulance but his condition was said to be serious when he arrived at hospital.
Doctor Leonardo Paloscia of the Cardiologic unity of the Civile Santo Spirito hospital said: "We did everything possible, but he never reacted".
Pescara chief executive Danilo Iannascoli told Sky Italia: "He looked me in the eyes when he entered the vehicle. Morosini fell, he tried to get back up but fell again. Our masseur realised what was happening."
Iannascoli also said the ambulance was blocked from coming onto the pitch due to a vehicle parked in front of an exit.
Italian press were alerted to Morosini's death initially by an "explosion of shouts and tears" from his team-mates who had come to the hospital, news agency ANSA said.
Police started to usher the press away but the official confirmation followed shortly afterwards.
Morosini's death comes just under a month after Bolton Wanderers midfielder Fabrice Muamba collapsed after suffering a cardiac arrest during his side's FA Cup quarter-final match against Tottenham Hotspur.
The 24-year-old's heart stopped for 78 minutes as medics battled to keep him alive at the stadium and then in hospital on 17th March.
But Kinshasha-born Muamba has since made incredible progress, boosting hopes that he will make a full recovery.
The incident led to calls for stringent heart checks to be made on professional footballers, following the example of those usually conducted so thoroughly in the Italian game.