While it is debatable whether or not Reid is out most talented player (Keane, Given and Dunne would surely have a case), I agree that it is non-sensical to not include him in the squad.
Personally I would have him in the team, he is surely worth a go in central midfield where we are not in the rudest of health. At this stage it is plainly not for football reasons that he is being left out. He has maintained a dignified silence until now but he must be fuming privately. I hope Trap will make his peace with him before the World Cup (assuming we qualify).