Barcelona boss Quique Setien has admitted that "not even the doctors know how long" Samuel Umtiti will be on the sidelines as the centre-back battles a knee problem.

The 26-year-old has only made 13 La Liga appearances for the Spanish champions this season and has been forced to miss his side's last three league games due to injury.

When quizzed on how long the France international could be on the sidelines, Setien conceded that even the medical professionals could not put a timeframe on his potential return.

"He is in an acute process with his problem. Not even the doctors know how long he will be out," Setien told reporters ahead of Saturday's league clash with Real Valladolid.

Umtiti, who has been linked with a move away from Camp Nou this summer, only made 15 appearances in all competitions last season as he struggled with a number of fitness problems.

The 2018 World Cup winner has a contract with the Catalan giants until June 2023.