The 27-year-old, who has three years remaining on his contract at Elland Road, is said to have handed in a transfer request.
However, the Championship club have moved quickly to insist that McCormack is not for sale and he is very much in their future plans.
The statement on the club's official website read: "Leeds United owner Massimo Cellino and the club would like to respond to recent media speculation regarding Ross McCormack.
"We would like to reiterate our desire to keep Ross McCormack at Leeds United. This desire includes keeping all of our best players as we look to build a stronger and successful squad for the 2014-15 Championship season.
"Leeds United may not be the richest club in the Championship, but we do not need to sell our best players in order to run the club successfully."
McCormack, who joined Leeds from Cardiff City in 2010, scored 29 goals for the club last season.