Leganes owner Felipe Moreno has confirmed Barcelona want to sign Martin Braithwaite.
The Catalans have permission to sign an emergency replacement striker for Ousmane Dembele after his season-ending hamstring surgery.
"I understand that Barcelona can do this if the rules say so, but I didn't think they could pick up a player who was already on contract. Yesterday, Monday, they called and said what they were thinking," Moreno told Sport.
"I can see that Braithwaite may be heading to Barcelona. I wanted him to do that too, but I've told them that we don't negotiate anything. Pay the clause or he will stay in Leganes."
Braithwaite's deal with Leganes carries an €18m buyout clause.