Alessandro Florenzi has gone under the knife to reconstruct the torn anterior cruciate ligament and meniscus in his right knee, confirmed Milan, and could be out for eight months.
The veteran Italy international sustained the serious injury during a pre-season friendly match in the United States of America.
He flew back to Italian soil and had the operation using arthroscopic surgery at the Ospedale Galeazzi S Ambrogio in Milan, performed by Dr Roberto Pozzoni.
Florenzi injury far more serious than thought
A statement from the club confirms it was an operation to reconstruct the anterior cruciate ligament and repair the meniscus in his right knee.
This is far worse than previously feared and initial estimates from Sky Sport Italia suggest Florenzi could be out of action for six to eight months.
The 33-year-old came up through the Roma youth academy and went on loan spells at Crotone, Valencia and Paris Saint-Germain before his transfer to Milan in 2021.
He has 288 Serie A appearances under his belt, scoring 28 goals and providing 33 assists, playing in a variety of roles including right-back, left-back and advanced midfielder.