To prove to the world that he was right to bring him in as a full back.
Now I dont see why this could not be tried again in future - perhasp when we are in a better league position, have the rest of the back six steady, and are playing a team with less of an attacking threat - and why it could still work, but I just don't think now is that time, because Atkinson is out and we cannot afford to get caught out again in tonight's game, particularly with the game on Saturday off as well.
For me it is Mous at CB or Long into CB and Forde at RB - no issue with Clare being used further forward for some or all of the game.