The Bluebirds have suffered their fair share of injury problems of late, especially in attack, with Jay Bothroyd the latest addition to a treatment room which already includes Ross McCormack.
But Ridsdale told the South Wales Echo: "I don't expect any more players coming in.
"As far as anybody going out, that is out of my control. If anybody comes in with a bid which matches our valuation of a player we would consider that. But, if I was a betting man, I would think the squad at Doncaster will be the same as that for the match against Newcastle."
Regarding the contract on offer to Joe Ledley, the Bluebirds chairman added: "It's up to Joe and his advisors to see if the numbers are what they are thinking about. I expect Joe to sign a new contract. There is a will on both sides for that to happen now."