Barcelona president Josep Maria Bartomeu has hit out at Arthur Melo after his AWOL antics.
The Brazilian is said to feel frustrated by his treatment since agreeing to leave the club this summer, but Bartomeu has promised to sanction the player for his behaviour.
"It's unacceptable, it's an act of indiscipline because there is no reason to justify not coming back with his teammates now that we will play the Champions League," Bartomeu told Sport.
"There will be a type of sanction and fine.
"He hasn't given a reason, he said it's his decision, that he's in Brazil and he won't come back."