The Spain international has long been linked with a move to Old Trafford.
“When you hear a club like Manchester United is interested in you it is an honour,” Silva is quoted by the Daily Express.
“I am very aware of the Premier League, and in recent years it has been the stand-out league in the world.
“If it came calling, especially if it was a club like Manchester United, it would be very hard to resist.
“I am happy at Valencia but every player has his price and if they get an offer they think is good business anything is possible.”
Silva has in the past been linked with Liverpool, Chelsea and Manchester City.
