"We've been in discussions about this for a couple of weeks. The player is keen for the chance to move on," said Killie chairman Michael Johnston.
"They have Champions League coming up and believe he can boost their chances.
"It's now up to Cillian and the club to agree terms and complete the deal.
"Obviously he was not involved in the team much towards the latter part of the season and he has decided this is the best option for his career."