AC Milan forward Antonio Cassano will undergo neurological tests in order to diagnose the mystery illness that left him hospitalized following Saturday's 3-2 win over Roma.
Cassano, 29, came on for the final 16 minutes at the Stadio Olimpico but then fell ill on the way back to Milan. The Italy international wanted to return home but was convinced to go to hospital by the club's chief doctor Rodolfo Tavana.
The former Real Madrid forward reportedly had difficulty speaking and moving and after an initial series of tests proved inconclusive Cassano has been transferred to the neurological department of the hospital where he will undergo tests on his heart and brain.
A club statement read: "Antonio Cassano felt unwell on Saturday evening's flight back from Rome. The player is undergoing tests at the Policlinico in Milan."
Cassano's wife and mother arrived at the hospital on Monday morning along with Dr Tavana, who said: "The boy was not well, we're investigating."
Milan coach Massimiliano Allegri painted an optimistic after spaaking to Cassano and said he was hoping the forward can return to action after the winter break.
He told reporters: "Antonio's doing really well, even on Saturday I got to talk to him for 20 minutes.
"At the moment the important thing is that he recovers and steers clear of danger. We hope to have him back as soon as possible, maybe after the winter break.
"From what I heard yesterday he seemed calm and relaxed. The whole squad is in shock and really sorry about what has happened to him.''
Milan vice-president Adriano Galliani said: "I spoke to Antonio five minutes ago on the phone, but we've already exchanged plenty of text messages.
"I'm sure he'll be fine, he's already feeling much better. All the squad are with him. We hope everything goes well, he's in good spirits and seems calm.''
Meanwhile, defender Philippe Mexes is to have an operation on his left hand which is likely to rule him out of France's international friendlies against the United States and Belgium later this month.
The 29-year-old injured his hand in training on Thursday, forcing him out of Saturday's victory at Roma.
He will go under the knife on Monday and is expected to miss the next two weeks, making it highly unlikely he will be named in Les Bleus' squad for the matches with the States on November 11 and Belgium four days later.
Dr Tavana said: "It's a simple procedure to stabilise a fracture in his left hand. Two small screws will be inserted and then he will have to protect the hand. Without this operation, the player would have had to be in plaster for 45 days."