Chadli suffered minor ankle ligament damage in the goalless draw against Liverpool.
The Belgium international is set to be out of action until the home game against Chelsea on November 29.
A statement read: “Further assessment and investigation has confirmed that Nacer Chadli suffered ankle ligament damage during our draw against Liverpool.
“The Belgium midfielder was forced off with the injury early in Saturday’s game and is expected to be sidelined for around six weeks.
“Our medical staff will continue to monitor his progress during his rehabilitation to determine when he will be ready to return to training.”
