The midfielder has withdrawn from Begium's squad ahead of their World Cup qualification matches against Serbia and Scotland and will return to England on Monday
The 24-year-old sustained the injury during Everton's 2-2 draw against Wigan Athletic last Saturday, while the Belgian Football Association announced on Tuesday evening that the midfielder is likely to be sidelined for three weeks.
Having withdrawn from Belgium's squad ahead of their World Cup qualifying fixtures against Serbia and Scotland, Fellaini will now return to Everton to be assessed by the club's medical staff.
"Marouane Fellaini is returning to Everton for further assessment of his knee injury," a statement on Everton's official website read.
"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"He was withdrawn from the World Cup qualifiers against Serbia and Scotland and had the injury scanned in Belgium.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."