Selling is all well and good - if the replacements are as good or better and cheaper. If not, then it isn't worth it. Which is kind of a circular argument. I expect one or two agents to unsettled at least one of our stars in the summer.
Say Guehi, for example, he's been injured, Richards looks good. However, Guehi has been injured - might not go for what he would have done, and try to think of cheap, good central defenders. There are only a couple that fit the bill - and they'd have to want to come here.
Say Eze, possibly could replace with a couple of players but they're going to be high fees, likely high wages. I immediately think of maybe Gibbs White, maybe Gallagher - any cheaper, any better? Maybe Barkley? Perhaps worth a shout but I'd rather Eze.
I'm not sure you can get another Olise. He needs a very high fee. I guess I'd take young, exciting, quick. Perhaps a couple fit the bill.
Doucoure - probably needs to come back before there will be interest. Don't think you could do any better than Wharton to replace him. We're not buying Lavia.
I think Andersen will perhaps get offers - probably quite high ones. If we can get a young English replacement for the same value then perhaps - but it's a risk.
It's not as easy as it all sounds when you delve into it.
I guess to reverse this: think of who's young and already doing well in a high enough league. Then think if they would suit us - or even consider us (for instance no one from Real or Barcelona are on their way to Selhurst), then consider who we could sell to buy them and how much profit we would make. You can then wonder if it's worth it. For instance, I'd take Branthwaite from Everton but would it be worth selling Guehi or Andersen to buy him? It's not an easy decision. Colwill similar. And any of these could be well overpriced and frankly well overrated.

We've supposedly been after Ronnie Edwards for so long a restraining order might be imposed, so possibly he might come in if Guehi goes. Eduoard has failed to live up to expectations so I don't think he'd be hard to replace. It was a miracle we got Olise for what we paid and I can't see that happening again. I guess if he leaves we'll see just how good Dougie and his team are in finding a replacement. You would think they've been planning for it for a while given last summer.

The only caveat I would put on that is that Olise, Guehi, Eze and Wharton were already getting rave reviews. Can we keep getting readymade stars for such good fees? Possibly. Munoz is a sign that they can also cast their net into lesser known waters with success.

Johnstone

Munoz
Andersen
Guehi
Lerma
Mitchell

Doucoure
Wharton

Olise
Mateta
Eze

If we can keep hold of them and if they all stay fit we’ve got a really good side now, that’s without accounting for any new signings, but as we all know ‘if’ is the magic word