Manchester United manager Sir Alex Ferguson has admitted that he is puzzled by star striker Wayne Rooney's poor form so far this season.
The 25-year-old England international, who is currently sidelined by an ankle injury, has scored just once for the Red Devils so far this term, but recently put pen to paper on new five-year contract.
Ferguson told The Sun:"I don't know the reason for his loss of form because it started in the World Cup.
"Whether some clubs have been filling his head in that period to affect him we don't know.
"The important thing is for us to put it behind us, but certainly something has been troubling him.
"I think that this (new contract) has been preying on his mind. When he saw the impact his decision made, it took him aback and he had a rethink."
Meanwhile, Ferguson has left Rio Ferdinand out of the squad for the Champions League trip to Turkey to take on Bursaspor, with the central defender joining Rooney, Jonny Evans, Federico Macheda, Anderson, Ryan Giggs and Michael Owen on the sidelines.