I actually personally disagree with all three of your answersdodger wrote: No.
1. He will be worth much more in even one or two years.
2. We won’t replace him with anyone nearly as good or his age.
3. It would send out the message that we are prepared to sell our best players, when we’ve finally had at least a couple of seasons of not doing that.
1) Potentially but is it the perfect storm now to sell him, defenders are in high demand and Manchester United are desperate, he is seen as the top young player, in 2 years time if he has not reached the elite level, bigger clubs will not take a punt on Diop.
Whats his max value?, Van Dijk went for 90 Mil, is it worth risking 60 million for the potential of 90 mil. In 2 years time, he could get injured, he could not progress to Van Dijk's level , But also in 2 years time, he will only have 2 years left on his current contract, if he plays hard ball, his value would be maximum 60 million anyway , if we don't sell him its imperative we make him sign a new contract to protect his value
2) On current ability, say he was 30 years old, Diop would be worth around 15-20 million pounds, he had a decent season but it was nothing better than Reid had during 2013-2015, personally think Balbuena was better last season, therefore we can easily buy a better current ability centre back or alternatively go for a younger centre back again e.g. Kabak the difference between Diop to Kabak will be less than in 2 years time if we buy a 19 year old for around 20 million , therefore we can replace Diop for 20 million meaning we have 40 million to improve the whole squad, in them 2 years Kabak may become a 60 million pound centre back meaning you have made the 40 million Diops replacement in the same timespan, but also can improve the remainder of the squad. This time last year had anyone heard of Diop? i trust Husillos to find another Diop
Personally i think we have 3 problem positions that we are not addressing this window, both fullbacks and central defensive midfield, with the remainder of the 40 million we could address 2 of these and therefore although centre back may get worse the overall squad may improve
3) I think this the exact message i want to send to the world, use us as a stepping stone. Lets be fair unless you grew up as a hammer, i don't want any player we sign wanting to dream of playing for us. They can win the champions league or the premier league, and who can blame them, we cant offer them this should be ambitious to play for Real Madrid or Manchester United. They should have the confidence they therefore all we offer them is the platform to parachute themselves towards these clubs indoing so we earn the profit but also get their ability towards our goals
Take Maxi Gomez as the example, if we show him Diop going to PSG or Manchester United, and say this could be you, score us 20 goals, and if we get 80million for you then you can go with our wishes. Clubs such as Benifica and Ajax have benefited from this model, its about believing your recruitment and management is better than your playing squad, and from his past signings, i believe Husillos can turn 60 million into 90 million quicker and more reliablly than Diop can get to that value
To reiterate, i don't want Diop to go, but everyone has a price and i trust Husillos