I've said since the end of last season that the CB pairing needs gutting. He needs to wade in in January and get reinforcements in...CB and out wide.
Then he'd have to do his business early... I actually don't think the centre-halves are the problem, and certainly not when Stones is back. Out wide really is an issue though - McGeady isn't good enough, Mirallas is inconsistent and Pienaar looks like his legs have gone.
I'd ship Atsu back to Chelsea and look for another loan and a permanent out wide.