We do but we won't do that unless walker himself accepts it's over. This is pure speculation on my part, could very easily be entirely false but I get the impression he's not someone who will willingly accept things he doesn't want to hear or face.
I reckon he probably still thinks he's capable of being the champions right back. Out of respect, we aren't going to look to dump him, it has to be a mutual thing and if he still thinks he's upto it, that isn't going to happen.
Believing the above to be true, the solution is we sign a centre back this windkw and then we can move akanji/stones out there or possibly the new centreback if he is adaptable.