What apart from the simple fact Pulis has no history of developing young talent?
He was taken in as back up when they had an injury crisis and as soon as senior players were fit they took his place. It wasn't to do with form that he was dropped, because Galloways form was fine, in fact they did quite well in the 3 games he started in if I recall correctly. It was just a poor choice of club and just because they're a premiership club, a "big club", shouldn't come into it for what should be obvious reasons.
I'm also pretty sure you can't place a recall option when it's a long term loan is between two premiership clubs.
Chelsea did with ake which is why they brought him back in January.