The Brazilian midfielder has turned down the Serie A side and looks set to sign for the Catalan club in the next few days
Barcelona are close to signing Gerson from Fluminense after the 18-year-old midfielder rejected a move to Roma.
The Serie A side offered €15 million for the talented youngster, but the player has his heart set on joining the Catalans and a deal is now expected to be reached over the next few days.
Barca paid €3.6m to Fluminense in May to have first option on the Brazil Under-20 midfielder, although that agreement runs out on Friday.
The Blaugrana – who are unable to field new players until January due to a transfer ban handed to them by Fifa last year – have offered only €12m to Fluminense so far and the Rio-based club insist they raise their bid in order to land the midfielder.
The Catalans are in constant contact with the player, however, and are sticking to their original offer in the knowledge that Gerson has told his club he is only interested in joining Barca.
The 18-year-old is aware he will be unable to feature for the Spanish and European champions until 2016 and accepts those conditions.
Head coach Luis Enrique is keen for Gerson to train with the first team before making a decision in January on whether he stays for the remainder of the season or goes out on loan to gain experience elsewhere.