MANCHESTER, England, Dec 23 (Reuters) - Manchester United's big-money signing Marouane Fellaini faces several weeks on the sidelines after having an operation on his wrist.
The club told Reuters on Monday that Fellaini had undergone surgery and said that manager David Moyes would provide more details on his anticipated return to competitive action at a news conference later in the day.
The injury means the mop-haired Belgium midfielder could miss both legs of United's Champions League last-16 clash with Olympiakos Piraeus in February and March.
Fellaini has struggled this season to replicate the form that persuaded United to pay Everton 24 million pounds ($39.25 million) for him in September.
He has yet to score a goal in 11 appearances for the Premier League champions.
The Old Trafford club, who are down in eighth place in the table, travel to former United defender Steve Bruce's Hull City side on Dec. 26.
($1 = 0.6114 British pounds) (Writing by Tony Jimenez,; editing by Pritha Sarkar)