He wouldn't have got much game time, so it's a good decision for him. And a great addition for York.
But where does that leave us in cover? Edgell and Lumb for fullback, and Sinfield in the halves? Then we are back to half a team reshuffle if Frawley and Croft are both out?
Leeds must need the cap space for a big signing. There is no other logical reason to let him go.