Redknapp is keen to bring in a new goalkeeper as cover for Heurelho Gomes.
Redknapp told Sky Sports News: “He is a top goalkeeper but he is going to cost an awful lot of money so he is not going to want to come as cover.
“I wouldn’t think Sir Alex would really want to sell him so I don’t really see that one as being a goer.”
He continued: “I think every day about the players I would love to have at the club but maybe that is just me dreaming.
“One has just gone to Real Madrid who I would have loved, Lassana Diarra. I took him to Portsmouth for £5million and they have sold him for £20million, what a player he is.
“But that was never going to happen. He is too expensive for us.
“The chairman has never been afraid to invest. Spurs gave always brought players in so if we find the right player is I am sure Daniel would back me 100 per cent.
“It is just finding the right people without paying silly money for them.”