The Merseysiders are in talks with the England Under-21 international, although they reportedly face competition from Newcastle for his signature.
Baines has already rejected a summer switch to newly-promoted Sunderland, but Everton remain confident of agreeing terms with the 22-year-old defender.
"We are at least part of the way down the road," Irvine told Everton's official website.
"But with the demands made by everyone these days, I'll only believe it's going to happen when it actually does happen.
"We have been talking to Leighton and hopefully sorting things out with him."
Everton are rumoured to have agreed a £6million deal with the Latics and Irvine believes that is a good piece of business.
"When you look at the prices that are going around these days, then £6m is not a great deal of money," he continued.
"Leighton has got real potential to play for his country. He's a good footballer, a nice passer of the ball, he has loads of energy and he is quick."