He hasn't exactly set the world on fire in Greece or at the World Cup. We've seen players who have had bad loan spells becoming excellent players and players who've done well on loan be ignored by Wenger. I'm sure he had his mind made up a while ago on what to do with Campbell.
As Maccy referred to, the first two matches have seen our sub options curbed by injuries and a red card. And he most likely won't be competing directly with Sanogo for a place anyway.
He could be one of those players that WUMger just doesn't give much of a chance too, but we should probably give it a few months before hysteria sets in.