Barca and Juve have been discussing a deal for the best part of two months which would see Arthur move to Turin for a fee north of €60 million. Pjanic would then join Barca for less than Juve pay for Arthur.
The Brazil international's reluctance to leave Camp Nou has been the only obstacle throughout the negotiations but, following a renewed attempt to change his mind, Juve now believe they are close to getting an agreement over the line.
A source close to the negotiations has told ESPN everything "has advanced this week" and, while sources close to Arthur said "nothing has changed," there is a growing belief he will accept the contract on offer at Juve, which is worth considerably more than he earns at Barca.
Arthur, 23, started Barca's 1-0 win against Athletic Bilbao on Tuesday but was substituted after an hour and coach Quique Setien said it is possible his form has been hit by the ongoing talks.
Sources told ESPN last week that Juve and Barca have already drawn up the framework for the player exchange, with Bosnia international Pjanic happy to move to Spain.
Both players would move in separate deals, to allow the clubs to include the incoming fee in this season's accounts, thus balancing their books following a tough time financially due to the coronavirus pandemic. The outgoing fees would be amortised over the length of the players' contracts.
Barca's need to bring in cash before the end of the month is particularly high. ESPN revealed in May the Catalan club needed to pocket €70m before June 30 based on a revenue plan drawn up at the start of the season which banked on receiving €124m in player sales.
Arthur joined Barca from Gremio for €30m in 2018 and throughout the last two months has fought his corner. He released a statement in April expressing his desire to succeed at Barcelona. In May, ESPN revealed he had told both Juve and Barca that he did not want to be involved in any exchange deal and wanted to stay put.
But with Juve coach Maurizio Sarri keen to make him the centrepiece of his midfield and Barca open to selling most of their first-team squad for the right price -- with the exception of Lionel Messi, Frenkie de Jong and Marc-Andre ter Stegen -- both clubs have continued to chip away at a deal.
Pjanic, who is seven years Arthur's senior, has been a Barca target in the past. He has made 170 appearances for Juve since signing from Roma in 2016 and sources said he is excited at the chance to move to the Spanish champions at this stage in his career.