The left-back asked to leave Glanford Park last week, with his agent claiming he was unhappy at only having 12 months left on his contract.
In response he was offered a new two-year deal, which the player has turned down - questioning whether his agent Nick Rubery was telling the truth when claiming he merely wanted job security.
West Bromwich Albion have been linked with a bid for the wantaway defender, but United will not be making him available for transfer.