"They (United) have been in touch with us and we will be starting negotiations very shortly, I would imagine," Dave Whelan told Sky Sports.

"United have been in touch with us over Antonio for the last two or three months, expressing an interest and actually putting cash offers on the table."

The Ecuadorian winger has reportedly attracted a host of suitors including United, Real Madrid and Chelsea after producing impressive displays last season.

But Premier League champions United appear in pole position to land Valencia as they aim to find a replacement for Cristiano Ronaldo, who is set to join Real Madrid.

"Those things have got to be picked up now. I think they (United) were waiting to see if Ronaldo actually went to Real, which has happened," Whelan added.

"Things will develop over the next seven to 14 days."