The 21-year-old, who is widely regarded as one of the best young defenders in the Football League, has been strongly linked with a move away from United in recent months.
Clough is not keen on losing the youngster, but has admitted that he would be prepared to sanction a sale if a bid that matches the club's value is received.
He told The Star: "As far as we're concerned, nothing has changed. If we get a bid that means we can strengthen two or three positions then it's something, of course, we would have to seriously consider, but that's not happened and we also want Harry to stay.
"If it doesn't happen, then the situation remains the same and Harry will start the season with us. The (contract) offer will still be there and we are happy to talk about it again if that's the case or he decides that's what he wants.
"But the decision will have to come from his side, not us, because they were the ones who made it (to postpone talks)."
Wolverhampton Wanderers are believed to be the favourites for Maguire's signature.