Or it could be that he is training with the first team squad, because that is where he is going to be this season. At 17 Roberts was bossing the U23s. A difficult season in a makeshift defence for Rochdale (they had loads of injuries), will not have turned him into a bad player. I still expect him to be playing for the first team at some point this season, why would Potter not want a left footed centre back, who is able to carry the ball forward and pass accurately short and long?
No arguments from me. I wasn't advocating a loan - simply answering Swanny's suggestion that arranging one would be financially problematic.