Chairman Krasner said in the Yorkshire Evening Post: "This is a good offer for the player and reluctantly we felt it was something we had to consider for a number of reasons.
"Of course we are disappointed to see James leave, but the choice the board had was whether to keep him and not have money to give Kevin or go ahead with the sale and have some money to spend.
"It's not been an easy decision and it's one we've not taken lightly, but we believe it will be for the good of everyone concerned.
"James is a Leeds lad and has done well for the club. He goes with our best wishes."