Barcelona announced on Sunday that they have an option to sign the Brazilian midfielder Arthur at the end of this season from Gremio.
The player could arrive in July for an initial fee of 30 million euros (37 million dollars).
The 21 year-old is yet to play for the Brazil senior side but has already represented his country at under-17 and under-20 level and could even be included in the senior squad for the Russia World Cup.
Commentators in Barcelona have likened Arthur's playing style to former Barcelona player Xavi and current captain Andres Iniesta.
Arthur is poised to join the club just as Iniesta looks set to leave, with a move to Chinese Super League club Tianjin Quanjian a possibility at the end of this season.
The club statement read: "FC Barcelona and Gremio de Porto Alegre have reached an agreement for an option to sign Arthur Henrique Ramos de Oliveira Melo.
"If the club take up the option on the player the price of the transfer is fixed at 30 million euros plus nine million euros in variables."
