United Want £2million plus add-ons for Sharp, who hit 32 goals last term, with the Canaries the only team to come close.
Wharton is allowing Sharp to talk to interested clubs, but insists the club have not accepted any offer yet.
"Sharp knows that both Wednesday and Wolves are a long way short of the asking price we want," he told the Scunthorpe Telegraph.
"We have made Billy a terrific offer to stay, and we have built in a clause that would mean Billy would benefit from a move if he stayed with us until the January transfer window."