The 21-year-old Spain international, who tore his anterior cruciate ligament (ACL) in November 2023, injured his right knee in training in August after featuring in Barca's opening two matches of the season.
"Gavi has had an arthroscopy to resolve a medial meniscus injury, which was sutured to preserve the meniscus. Recovery time is estimated at around four-five months," Barca said in a statement late on Tuesday.
Barca are second in LaLiga, trailing Real Madrid by five points but with a game in hand. They visit Real Oviedo on Thursday.