Clark originally signed the Northern Ireland international on an emergency loan in March, only to swiftly extend his stay until the end of the season.
But the former Newcastle player could go back to his old club a third time for Ferguson as he plots a Championship play-off push next term.
Clark told the Chronicle: "Fergie came in for us last season and was brilliant.
"He was great at left wing and left-back, he made goals and scored goals.
"He's a big part of what I am trying to do. I'm trying to turn the club around.
"With the financial situation, the young players I've got are important. I gave six Academy players their debuts this season."
Clark is also understood to be interested in Wales U21 left-back Paul Dummett, who has been told he can leave the Magpies on loan for first-team experience.