The Scotland international, who has netted five times this term, revealed to local radio after Saturday's 1-1 draw with West Brom that he had received no contact from the club about extending his current deal beyond the end of the season.
But, speaking ahead of the Tigers' EFL Cup quarter-final with Newcastle at the KCOM Stadium on Tuesday night, Phelan confirmed Hull would address the situation shortly.
"That will be taken care of in due course," head coach Phelan said. "We will pay attention to that as he is an important football player. We will be dealing with that pretty shortly."
Another player in the same situation is Harry Maguire although he has had some contact about fresh terms.
The former Sheffield United defender, having struggled to secure regular first-team football, is expected to be given a chance to impress against Newcastle.
"There has been bits and bobs between my agent and the chairman, not too much, but hopefully in the coming months it will get sorted," Maguire said.
"As a footballer, I want to play every week. I want to play regular football but you also want the security of the length of the contract.
"As you know, I am going into the last six months of the contract so hopefully something can be sorted."