hey mate, where are you finishing in the league this season? or what is your aim? if you finish high up and do well, the player will change his mind (sometimes)
If you want to take the chance, offer him out and 10x the amount he is worth now, transfer list him and see what happens:
1) some clubs may offer a lot of cash for him
2) sometimes the player actually asks to stay and will end up asking for a new contract
3) take him off at least 3 months before his contract will allow for free signing (i.e: 9 months left) to ensure he will come right and want to sign
if all this fails, just try and sell him for at least 3x what he is worth