The Scot celebrated winning the Sky Bet Championship Player of the Month award by scoring his 16th goal of the season on Saturday in the 3-3 draw with Watford.
Manager Brian McDermott knows McCormack's form is attracting plenty of interest, but insists the striker is not for sale. He said: "I don't think this is a selling club any more. We got offered a certain amount of money for Ross in August and I don't think that would buy a part of his body now.
"He's not even at his peak yet. He'll get better and better. He was bright and vibrant and he makes things happen. We need the big players to come up with the goods."