The 26-year-old has recently been strongly linked with a move to Italian giants Juventus.
“I am aware of rumours of Juventus’ interest, but for my part there is nothing concrete,” Valencia’s agent Diego Herrera Larrea told calciomercato.com.
“In the past, some Italian clubs were interested in the player but not in recent times.
“I don’t think that Juve has spoken with Manchester United because I was not informed, but I cannot exclude it as a possibility.
“I see it as very difficult that he leaves United, first of all because he has recently signed a new four-year deal and because he and his family are very well in Manchester.
“But in football, never say never.”