Spurs have been surprisingly quiet in the transfer window and are battling to keep Luka Modric from moving to Chelsea.
Manchester United boss Sir Alex Ferguson admitted this weekend his side face a tough challenge in defending their title as a result, but did not list Tottenham as contenders.
And Redknapp said in The Daily Star Sunday: "If you want to be a top-four side, it's difficult because we can't pay those kind of wages.
"Fergie didn't mention us when he spoke of title contenders and it's looking that way."
Meanwhile Redknapp is waiting to learn the extent of the injury Steven Pienaar suffered during Saturday's 2-1 friendly win over Athletic Bilbao.
Redknapp said after the game: "Steven Pienaar picked up an injury. He might have torn his groin. I think we're going to take him to a specialist and have a look at him. We'll see how it goes."
If a tear is confirmed, Pienaar would be ruled out of Tottenham's opening Premier League game against his former club Everton next weekend.
Source: Team Talk
Source: Team Talk