Even beside Gordon, Casey has struggled.
As I have said before, I can see the attributes Casey brings to the team. He is full of energy and great at disrupting things further up the field, and can be a wrecking machine in the oppositon box at set pieces.
Defensively, he is often out of position, loses his man regularly, and puts us back under pressure with his poor passing - either passing to the opposition, or making the wrong choice of team mate.
It's not like we haven't given our central defenders an opportunity to prove themselves over the past few seasons. They have just continuously failed to deliver. I'm sure it gets inside their head too, and they all might benefit from a fresh start at a new club as much as we'd benefit from a new central unit.
I honestly can't think of any combination I see line up on a Saturday and think "that looks solid"