Fiorentina general manager Joe Barone is on life support following a cardiac arrest, the club said on Monday.
Barone fell ill Sunday at the team hotel, shortly before Fiorentina's match at Atalanta, and was rushed to a hospital in Milan. The match was subsequently postponed.
Fiorentina said Sunday night that Barone, who turns 58 on Wednesday, was in "critical but stable" condition.
On Monday, the club said Barone remains hospitalized in the cardiac intensive care unit at San Raffaele Hospital in Milan.
"Joe's vital functions are being supported by artificial mechanical support techniques. No prognosis has been set," the club said. "The Barone family, the Commisso family and all of Fiorentina thank San Raffaele and all of Prof. Alberto Zangrillo's team for the work they have done since Joe was hospitalized."
Barone was born in Italy but raised in New York. His wife, Camilla, rushed up from Florence on Sunday and his four children arrived from the United States on Monday morning.
Fiorentina coach Vincenzo Italiano and several of the players also went to the hospital on Sunday. Italian media reports that some of the players were present when Barone fell ill.
Two weeks ago, Fiorentina marked the six-year anniversary of the death of captain Davide Astori, who was found dead in his hotel room after a cardiac arrest before a match at Udinese.