Napoli will be without Alisson Santos until December after the Brazilian suffered a moderate strain to the biceps femoris muscle in his left leg.
The Serie A club confirmed the injury in a statement, with the 2002-born player now expected to miss almost the rest of the year.
His absence means the Tuscan coach will not be able to select Santos for Napoli’s matches against Roma, Monza, Juventus, Porto and Lazio.
Napoli had already been without Santos when they beat Norwegian side Bodø/Glimt in their Champions League match the previous day.