United boss Sir Alex Ferguson is keen to bring in Valencia as a replacement for Cristiano Ronaldo, who is set to join Real Madrid.
He told Sky Sports News when asked about Valencia: “They (United) have been in touch with us and we will be starting negotiations very shortly, I would imagine.
“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.
“Those things have got to be picked up now. I think they were waiting to see if Ronaldo actually went to Real, which has happened.”
He added: “Things will develop over the next seven to 14 days.
“The master, which is Sir Alex [Ferguson], he makes his moves when he is ready. He has strong interest in Antonio, there is no question in that.
“He had him watched practically every, single match last year. He has got a very strong interest in him. We are just sat on the fence now.”
“We are not desperate to sell Antonio, I’m telling you. If I can keep that lad, I’m going to keep him. He is one brilliant player,” added Whelan.
“So there is no pressure on me, or our football club to sell him. If Man United don’t want to make a (written) offer, I’ll be delighted and we will have him in our team next season.”
He said: “What is difficult is to stop a lad like Antonio Valencia, who has got ambition. It is difficult to stop a footballer, who wants to get to the very, very top of the ladder.
“I would never stand in the way of a footballer who can go to bigger and better clubs, and you can’t get bigger and better than Man United.
“If Antonio Valencia says to me, ‘chairman, I want to go to Manchester United’ and we get the right fee, the deal will be done.”