The Catalans accepted a bid worth £72.5 million ($91m) for the midfielder, while talks continue over Juve star Miralem Pjanic, who is wanted at Camp Nou.
Arthur has been at the centre of a possible swap deal involving Juve midfielder Miralem Pjanic, though talks with the Bosnia international are reportedly still ongoing.
Arthur joined Spanish giants Barca from boyhood Brazilian club Gremio in 2018.
The 23-year-old, who impressed in his maiden campaign, has made 26 appearances and scored four goals in all competitions this season.
Juve's Pjanic – in Turin since leaving rivals Roma in 2016 – has featured in 35 matches in 2019-20.