in some ways I think hes been a little unlucky. On 2 or 3 occasions when he has found some form something has curtailed it, either a change of manager, an injury or something like a lockdown. Obviously if he was truly top draw, those things wouldnt matter, but theres a layer of players below that, who are probably ok, but need some fortune and I would put him into that grouping.
I think his mindset is not really suited to being a top defender. Being a defender is about sending danger, and proactively rectifying it. I dont think he has those instincts at all.