Barcelona sporting director Robert Fernandez reportedly watched Gremio midfielder Arthur as his side won the 2017 Copa Libertadores final against Lanus on Wednesday.
According to Joaquim Piera of Sport, Fernandez also met with the 21-year-old's agents, and Barca now "know the player would prefer a move to Camp Nou," although Manchester United have also been linked.
Piera added Arthur's contract with the Brazilian club runs to 2021 and includes a €50 million release clause, while there is no possibility for Barca to sign him up now to join at a later date.