So the hefty release clause has been triggered then as mentioned by Brin

I would imagine there's a game going on here between club and player.
Posh want him sold now because they won't get anything in the summer but the player wants to delay signing for any new club until June because he's probably going to be able to negotiate a higher salary as his new club won't have to pay a transfer fee.

Hopefully he will be frozen out on Saturday as he is a good player