Bayern Munich have agreed a €40 million transfer fee with the Bianconeri for the Chile international, who joined the Old Lady from Bayer Leverkusen in 2011.
Vidal played a key role in Juve's revival, helping the Turin outfit win four successive Serie A titles and reach the final of last season's Champions League.
However, Marotta has now admitted that the 28-year-old is now set to become the fourth big name to leave the Italian champions this summer.
"Vidal has expressed his desire to embark on a different experience, just like [Angelo] Ogbonna, [Carlos] Tevez and [Andrea] Pirlo," the Bianconeri official told reporters on Monday.
With Vidal on his way to Bavaria, speculation is intensifying that Juve will attempt to persuade Bayern to part company with Mario Gotze, while there has also been talk of a move for Schalke's Julian Draxler.
However, Marotta is keeping his cards close to his chest, adding: "Gotze is a Bayern player and we are not in talks for him.
"As for Draxler? I don't know who'll arrive at Juventus; we only know the kind of player we want.
"The first aim is to have our squad complete and ready for the start of the new season.
"It's our duty to maintain our trend of success by reinforcing a winning model.
"Our aim is to a) equip the boss with a competitive squad and b) ensure the balance sheets are kept in good order.
"We're happy that we've lowered the average age of the squad. We're already a competitive side.
"We'll plug the odd gap in the squad if and when the right opportunity arises."