Rooney sensationally admitted earlier in the week that he would not be signing a new deal at Old Trafford, citing concerns over the club's transfer policy and his own desire to win trophies.
That has bemused Redknapp, who regards the Red Devils as a dominant force on the domestic scene, an understandable view given they claimed the Premier League crown three years in succession before losing out to Chelsea by just one point last term.
White Hart Lane chief Redknapp feels that the offers of vast wages on offer at certain clubs can turn players' heads, and also bemoaned the impact of agents on the modern game.
He told The Sun: "Rooney has his own reasons for wanting to leave Old Trafford and I just cannot begin to imagine what on earth they would be. He is already at the biggest and best club in the country, so where does he go to from there?
"Playing abroad brings its own set of problems and, who can say with certainty, that it would satisfy Rooney's demands and needs, whatever they may be.
"I have to say that part of the problem is money. If you see a player earning £200,000 a week, a player who is nowhere near as good as you, of course you are going to think 'I want some of that'.
"I wouldn't go as far as to say players are motivated by money. The biggest world stars play football because they love the game, but through that life, fabulous riches can come with it. Money can be unsettling, however, with agents engineering moves long before managers know what's going on these days.
"If there is anyone out there, who, for one second, imagines agents do not manipulate transfers, then they are not living in the real world."
Redknapp feels the Rooney saga demonstrates that leading players now hold all the cards when it comes to negotiating their future and fears Ferguson may have no option but to ship the wantaway striker out should he cause dressing room divisions.
He added: "All the power in football these days lies with the top players. It does not rest with the club, it certainly doesn't rest with the managers and quite frankly, some contracts are not worth the paper they are written on.
"If players want to leave and they are under contract, they seemingly can almost break their contracts at will. Once any player has decided he wants out, that's it, he's gone.
"There is absolutely no point in keeping him because it will cause unnecessary unrest in the dressing room and end up costing the club a shed-load if it is a top star who is involved."