David Silva's agents have admitted that 'big clubs' have asked about the Valencia star's situation, although he is only thinking ahead to next summer's World Cup.
The 23-year-old has previously admitted he was the subject of a large bid from an English club in the summer.
It is thought Manchester United have contacted the player's agents, Amadeo Rengel and Julio Llorente, to ask about a possible bid, although the club is said to want to wait until next summer to evaluate the situation.
But Real Madrid and Barcelona are also thought to be interested in signing the Spain international.
His agents said: "Now Silva only thinks to play in and arrive well to the 2010 World Cup, but we can not deny that big clubs have asked about his situation and we transmitted the question to Valencia.
"The decision rests with Valencia but Silva will also decide at the right moment - but at this moment we are very calm."
Silva was expected to depart the Mestalla in the summer, along with team-mate David Villa, as Valencia looked to ease their precarious financial position.
But the pair stayed and Silva is tied to Valencia until 2013, with the club thought to value the 23-year-old at 40 million euros.