Milan defender Mateo Musacchio has undergone keyhole surgery on his left ankle and will be out of action for four months.
The Rossoneri confirmed last week Musacchio would require an operation but did not put a timescale on a return at the time.
It has now been announced Musacchio, who has been struggling with the complaint for several months, will play no part in the remainder of the 2019-20 Serie A campaign and will miss the start of next season.
"AC Milan announces that Mateo Musacchio has undergone keyhole surgery to his left ankle, performed by Prof. Ramon Cugat, with Club doctor, Dr Lucio Genesio, in attendance," a club statement read.
"The surgeon pronounced himself satisfied with the operation. The estimated recovery time is four months, barring any complications."
Musacchio has made 18 top-flight appearances this term. Milan returned to top-flight action following the league's three-month coronavirus-enforced break with a 4-1 rout of Lecce.
Stefano Piolo's side are seventh in the table and face fifth-place Roma at San Siro on Sunday.