"Marouane Fellaini is returning to Everton for further assessment of his knee injury," read a statement on the Toffees' official website.
"Fellaini picked up a knock during the 2-2 draw with Wigan Athletic last weekend and although he managed to complete the game, the significance of his injury only became apparent 48 hours later.
"He was withdrawn from the World Cup qualifiers against Serbia and Scotland and had the injury scanned in Belgium.
"The Blues medical team have reviewed his scans and will assess him fully when he returns to Finch Farm on Monday."
Fellaini has scored three goals in eight matches for the Merseysiders so far this season.