Brighton boss Roberto de Zerbi is convinced by the potential of young pair Billy Gilmour and Jan Paul van Hecke.
Midfielder Gilmour and defender Van Hecke are playing the best football of their burgeoning careers this season.
"Our policy is to improve the players and sell them when it is possible," De Zerbi said. "It is a normal thing and we have to accept it.
"We have a lot of potentially great players, not only Estupinan and Joao Pedro but also (Evan) Ferguson, (Facundo) Buonanotte, Jackie (Hinselwood). But JP and Billy Gilmour are becoming great players.
"They are top level, both."
