Barcelona directors Robert Fernandez and Andre Cury have been pictured with highly rated Gremio midfielder Arthur, who was wearing the Catalan club's home shirt in the photograph.
Sporting director Robert spent the last week in South America watching Arthur, who has a €50 million buyout clause, lead his Gremio side to their first Copa Libertadores trophy since 1995.
Arthur was named as man of the match in the second leg of the final, with the Brazilians competing a 3-1 aggregate win against Argentine side Lanus.
Images have since emerged of the 21-year-old posing for photographs with Robert and Cury, Barca's representative in South America, in Porto Alegre on Friday.
Diario Sport reports that Robert dined with the player's representatives in the Brazilian city earlier in the week to discuss if their client would be open to a move to Camp Nou.
Gremio vice-president Odorico Roman confirmed the club were aware of the growing interest in Arthur, who was called up by Brazil coach Tite in September but has not yet made his full international debut.
"We have information that Inter, Atletico Madrid and Barcelona are interested in the player and have had representatives watching our games," Roman told FCInterNews.it.
"There is a €50m release clause, but if a club really wanted to sign him, they'd have to send us a proposal. We would evaluate and decide whether to accept or not.
"Our intention is to keep Arthur with us for a little while longer. We think he can remain for another one or two seasons and give a big contribution to our cause."
Arthur has drawn comparisons with Xavi Hernandez and Andres Iniesta in the Catalan press this week and Roman describes him as "an athlete with immense quality."
He added: "I'd say it's rare to find midfielders of Arthur's level in the world right now."
Gremio only own 70 percent of the player's rights, with the other 30 percent divided among his family.