The 18-year-old got injured in Barcelona’s 5-2 triumph over Real Betis at the Nou Camp on Saturday to end a four-game winless streak in the league.
Fati’s ruptured meniscus operation was carried out by specialist Dr Ramon Cugat and was a success. However, Barcelona has said his return would not come until approximately March.
The youngster will be unavailable for international duty with his national side, Spain, while boss Luis Enrique will have to look for a suitable replacement when the national team play against the Netherlands in a friendly before taking on Switzerland and Germany in the Nations League.
The Spain boss, Luis Enrique, handed Ansu Fati his first Spain call-up during the September internationals, and the teenager rewarded his faith by becoming the youngest player to ever score for Spain – breaking a 95-year-old record – with a goal against Ukraine.
Fati has become a regular for FC Barcelona since the start of the campaign since his debut last season. He has found the back of the net five times this season and provided two assists in 10 appearances across all competitions.