The capture of England international Crouch from Liverpool for £11m has left Redknapp with little money left to spend in the remainder of the transfer window.
"We really need to shift one or two if we are going to raise some money to bring anyone else in now," he told The News.
"Crouchie's in but now we need to find the money if we are going to try to finance another deal. Business is business. If you want to get a couple more in now we have got to generate a bit of money.
"If we sold somebody, a couple of players we can afford to let go, then there's one or two players I would love to bring in. But unless we move one or two out it's not possible.
"When you start talking about the type of players we are trying to bring in, no disrespect to Djimi, but his money doesn't buy you Wright-Phillips.
"You would like to have him for sure, but he's good money and at the moment we haven't got the money.
"It's not easy to shift people out, it's hard. Someone has got to want them and unless you get good offers for people then they stay. We've spent some money already this summer so money's tight now, so it's not easy."