Umtiti played the full 90 minutes for Barca in their 2-2 draw at Celta Vigo last Saturday and was under the spotlight after that match due to a lack of mobility and also his poor positioning in the Galicians' opening goal at Balaidos.
"The first team player Samuel Umtiti has a problem with his left knee and will undergo conservative treatment," Barca said on their website on Friday.
"The player is not available and his recovery will dictate when he can return."
The World Cup winner has endured a series of knee problems since starring in his debut season at Camp Nou and – by his own admission – forcing his fitness to play at Russia 2018.
Umtiti, who is 26, has made 18 appearances for Barcelona this season in all competitions and will definitely be sidelined for the Catalans' trip to Villarreal in LaLiga on Sunday.