Barcelona have a deal to sign Miralem Pjanic from Juventus for an initial €60million, with Arthur having agreed to move in the opposite direction in a separate arrangement.
Pjanic will put pen to paper on a four-year contract with Barca and join them at the conclusion of the 2019-20 campaign. The transfer includes an additional €5m in variables.
Earlier on Monday, LaLiga's champions confirmed Arthur will join Juve from next season for an initial €72m. The Bianconeri are yet to reveal the details of the Brazil international's contract.