Everton's Belgian midfielder Marouane Fellaini is set to miss the rest of the season due to an ankle injury which requires surgery.
The 22-year-old was injured in the Merseyside derby defeat to Liverpool ten days ago, suffering the knock in a tough challenge with Sotirios Kyrgiakos which saw the Reds defender sent off at Anfield.
Fellaini was forced to leave the field soon after and subsequent tests have revealed serious ankle ligament damage.
Toffees boss David Moyes told the club's official website: "He's not good, he's going to have an operation.
"He's got a similar injury to (Arsenal's) Robin van Persie and it's probably going to keep him out for six months."
Fellaini joined Everton in the summer of 2008 from Standard Liege and has since scored 12 times in 69 appearances, as well as being cautioned no less than 20 times in all competitions.