I am telling you right now there is no way Carlyle likes a guy who is not completely ready to handle the defensive responsibilities play big minutes on the backend. Having him up for spot duty on the PP is very ill advised.
Do you see him playing better than Phaneuf, Gunnarson, Fraser, Holzer, or Franson. And I haven't even mentioned Gardiner. He can play big minutes with the Marlies and will be up when he is ready.
RC took a one game look at Gardiner and decided he wasn't ready to play the game they are playing now.