Roma's Brazil international defender Leandro Castan has undergone surgery to relieve pressure on his brain after suffering acute dizziness.
The three-and-a-half hour procedure successfully removed a cavernoma, clusters of abnormal blood vessels in the 28-year-old's brain.
Roma say the centre-back woke after the operation and was breathing unaided.
But the former Corinthians man, who has made one Serie A outing this term, will stay in intensive care for 24 hours.
Castan made 36 appearances as Roma finished runners-up in the Italian top flight last season.
In the last two seasons, the Brazilian has appeared in 66 of his club's 76 league games.