Question is; does the club even accepts that?
I think this is huge part of the problem tbf.
Let me explain:
People have been quoting capology for salary of player,
I don't believe any site has accurate data of salaries but for ease of discussion let's assume it is accurate
https://www.capology.com/club/barcelona/salaries/
So
Martin Braithwaite earns 6M gross salary, seems ok right? Not that much in comparison to Barca salay.
BUT
Most of our players has their market in Spain mainly, they stayed there for years, possibly had their best success there, and usually Liga clubs make the most sense to move there. This is usually the case for most big clubs in top leagues anyway.
So let's take a look at some Liga clubs:
Celta: Denis is paid around 4.8M, but second highest is Aspas at 2.6M. No way a club like that make Martin a better paid player.
Espanyol: Raul De Tomas is highest paid at 2.7M, again no way they pay more for Braithwaite.
Getafe has
Djene at 2.2M, Mallorca top earner is less than 1M, Osasuna at 1.5M, Rayo at 1.2 etc
Now slightly richer clubs like Betis has Fekir at 6.7 but 2nd best paid at 4.2
Sociedad is even worse, highest at 4.4M
Valancie only 2 players above 4M.
Only 2 clubs that pay 6M as normal salary outside of big 3 is Seville and Villarreal.
So basically, unless those 2 are interested, the truth is the regular rate for a player like Braithwaite is around 2.5M at best. If you extremely lucky you get a club willing to pay him 4M.
Thing is, even outside of Spain isn't better. Outside of CL clubs that doesn't want him, only EPL clubs can pay that rate and even then most lower half of the table clubs will be making him top 5 or 6 earner to get him. And probably no one there wants him.
So basically, our previous board paid him like a top player in a team that is top 6 in Spain, when he was a top player in relegated team. The gap is almost 3 times the salary.
Can't blame the board for asking him to leave, can't blame him for wanting his money, can't blame other clubs for not wanting to pay him.