The Robins want £500,000 before they let the player speak to a possible buyer.
He also confirmed that United have not spoken to two clubs regarding strikers linked with a move to Glanford Park.
"We have not spoken to Chesterfield about Jamie Ward and we have not spoken to Mansfield about Michael Boulding," he said.
"What we are going to do is bring in another striker who can help us score goals, to add to the three players we already have here, who I am very happy with."