Southampton saw their approach, understood to be in the region of £6million, rejected in the summer, while Arsenal and Liverpool are among a number of top-flight clubs reported to be monitoring his progress.
Clark said: "The only official bid the club have had is the one that was turned down in the summer from Southampton, just as I was taking the job.
"That's not to say we haven't had lots of interest in Jack and people asking the question.
"But, in terms of somebody actually putting down that they want to take him and what they're willing to pay, that hasn't materialised.
"With my football manager's head on, I don't want that to happen. But, in terms of the future of the club, it's been talked about already by the chairman that it probably needs to happen."