The two deals are disconnected, so this is not officially a swap deal, with Arthur set to switch to Juve for €70 million (£63m/$79m) and Pjanic poised to move in the other direction for €60m (£55m/$67m).
It represents a significant and rapid U-turn on the player’s part, as it was previously indicated that he wished to stay at Camp Nou, despite being flattered by the interest of Juve.
With the clubs having already agreed terms, it is expected that the deal will be hurried through with Barca eager to complete the transfer by June 30 so they do not finish the year in a negative financial position.
Should the clubs fail to reach a final agreement by July 1, Setien's side will expect Pjanic's value to depreciate by €10m (£9m/$11m), thus increasing the total package for Juve.
Previously, Maurizio Sarri, boss of the Italian side, had hinted that a transfer could be close.
Speaking at a press conference, he said: “On Pjanic, I don’t know what the situation is but right now we’re relying fully on him. It seems to me that he is improving in terms of his performances.
“Arthur is a Barcelona player and it would seem bad if I started to talk about him. I didn’t like it when Quique Setien spoke of Pjanic, who is my player, and I don’t want to speak about anything in an absolute way. The club have not given me any communication about it.”
Central midfielder Arthur joined Barcelona in 2018, making the switch from Brazilian side Gremio on the eve of his 22nd birthday.
He featured 44 times in his first season in Spain as Barca lifted the league crown but this season he has been troubled by niggling injury problems and has played only 27 matches, scoring four goals.
Following a disappointing performance in Tuesday’s 1-0 victory over Athletic, Setien admitted the player had his mind on a transfer deal.
“I'm sure it's affecting him, yes,” the former Real Betis coach admitted. "I'm very happy with what he's doing, he's an important player for us and we'll try to get the best out of him.
"Given how things are we need all of our players and we'll try and isolate ourselves from this situation and the media who are reporting on and talking about these rumours. We need him to be focused. It's true it is a difficult situation but we have to overcome it somehow."