He is costing them 25m to sit on the bench, they do not want him there. How is he worth more to them?Why would PSG let him go for a small fee when he is worth much more to them, that doesn't make any sense?
Despite not having a market players still hold some value, letting go of someone like Neymar who has 4 years left on his deal represents huge value to PSG.
Why would we let ndombele go for a small fee.