"There's enough going on in Joey's life. The last thing he would want is an opinion from well outside from me," said O'Neill.
"There was nothing at all in stories that we were interested in him, regardless of off-field activities or anything.
"We have a number of central midfield players in our team and I wasn't chasing anybody. I haven't made any enquiries whatsoever.
"He's a very fine footballer. Newcastle spent £5.5million on him.
"You wouldn't command that sort of fee if somebody didn't think you were worth it.
"I suppose I'm probably not the best judge, but people like Stuart Pearce, Kevin Keegan and Sam Allardyce, who all worked with him, those people were prepared to take that chance.
"I thought he played very well for Manchester City the other year when they beat us under Stuart Pearce.
"Most of it will be up to him but what he will have found more than helpful, is that managers like Kevin Keegan and Joe Kinnear are giving him a boost by standing by him."