Firstly, any 'agreement', formal or informal, will undoubtedly still include us selling at a price that is acceptable for us. We are not just going to tell him he can leave regardless- it is still on our terms.
Secondly, who's to say that having VVD in the side for another season won't be worth as much or more than the value we might lose on him? Each place in the league is worth about £2million, plus extra tv money. If we lose £10million off his value but finish a few places higher than we would have, we will have done well.