Roma centre-back Leandro Castan will undergo brain surgery because he has a cavernoma - clusters of abnormal blood vessels in the brain.
The condition 'does not represent a threat to his life' said a club statement.
The 28-year-old Brazilian has played just one match this season, in September against Empoli, but suffered acute dizziness and had to be taken off at half-time.
A statement read: "After the Empoli v Roma match, Leandro Castan suffered a bout of acute dizziness.
"The player underwent medical tests in the days after the match, which revealed a congenital vascular alteration in his brain, a condition more commonly known as a cavernoma.
"Inside the cavernoma, the tests revealed a small edema and, as a consequence, temporary swelling. This was the cause of the symptoms reported by the player, which subsided of their own accord within a few days.
"Although the cavernoma does not represent a threat to the player's life - indeed, he is currently in peak physical condition - he is at risk of reoccurrences.
"Therefore, the medical staff, club and player have agreed that he will undergo neurosurgery at the beginning of December in order to definitively cure the problem. This will allow him to resume regular competitive sporting activity."
Reports in Italy on Monday morning suggest that the operation, originally set for December, could be brought forward, perhaps even to this week.
Castan is likely to need months to recover.Reuse content