Scunthorpe chairman Steve Wharton has set his asking price for Sharp at £2m plus add-ons, a price no club has yet been willing to meet.
But it will still be Sharp's choice if he goes - with Scunthorpe offering him a new three-year contract to stay which would make him the highest-paid player in the history of the club.
McCarthy is expected to complete a deal for Southend striker Freddy Eastwood next week, while Norwich City are also chasing both strikers.
"There are a few we're interested in, and Sharp is not the only one," said Canaries boss Peter Grant.
"Freddy Eastwood likes scoring goals, and is also one that has impressed me."