Ernesto Valverde's side are keen on adding another attacking outlet to their ranks this summer with question marks remaining as to precisely what Ousmane Dembele can offer the side and Willian has quickly emerged as their top target.
According to the aforementioned source, the player's agents have already touched down in the Spanish city to attempt to force through a move for the 29-year-old.
Despite having told the 'Blues' of his interntion to leave, Chelsea are refusing to make his departure a simple affair.
Nevertheless, Maurizio Sarri's desire to have a happy squad that is prepared to play in his image means that Willian's departure looks like the best solution for all concerned at this moment in time.
Eden Hazard's preference for a move to Real Madrid appears to have pushed Barcelona towards Willian, who impressed against Barca in last season's Champions League.
With Chelsea missing out on a place in Europe's premier club competition this season, Valverde has seen the perfect opportunity to lure the Brazilian away from Stamford Bridge.
Should the deal be completed, Willian will join Philippe Coutinho and Arthur on a long list of Samba stars to represent the Catalan side