There are a few gambles with life and some pay off.
1) Keeping him without him signing a new deal, I don't see as a gamble too much as it gives us a chance that we stay up which probably brings in another £40 million which should see us be able to look at the overseas market if he was to leave on a free.
Con with that is no sell on clause if he does go onto be a massive hit
2) Selling him now - price has to be right, if Alex Scott price for Bristol City is right (already turned down rumoured bids of £20million) and now rumoured they want £25million I think we should be looking at £30million +
Pros to the above: £30million in the bank
An Absolute must - any contract deal must come with a decent sell on clause, if he signs say for 4/5 years at Marseille (not in the know) he would be reaching a peak in his career, if he reaches full potential at a champions league club. A Saudi club or a European giant will be looking at least 3 x the current value.
Cons Apart from Ndiaye going he is on by all accounts a small wage budget offering excellent return for money. Bringing in a player for £25-30million hasn't been one of our strongest points in the past and is also a gamble so it could be the case we are looking at 2 players however that then brings a point of integration to the squad, the team already has a new ID from that of a few weeks ago with 3 new additions, could adding another 2 upset the dressing room or is that a chance we might have to take.