He watched City play at Reading last week and knows some of the City squad.
"I thought that at Reading obviously with the players that they have Cardiff want to play football. There are a few of the players I know," said O'Neill.
"I'm sure if you asked Dave Jones then promotion or the play-offs would be his priority, but that would not mean he will not be coming here with the intention of upsetting us. They will probably go out there feeling they haven't got a great deal to lose.
"They had that great run in the FA Cup not long back and probably three or four rounds before the final then they thought it might not go their way, but a couple of wins and confidence gets high.
"I'm not too sure how they will approach the game. I know how we are going to approach it, we just want to win."
Bluebird Peter Whittingham came to Cardiff from Villa Park.
"I know young Peter Whittingham very well of course", O'Neill continued "because I sold him to Cardiff. He was never able to establish himself regularly in the side here and that is what he wanted, but I know he has a lot of talent."
Hopefully Whittingham has one of those games where he shows up and not one where he can be prone to go missing.