Barca defeated the Bianconeri in the 2015 showpiece, but Marotta says things are now different with the Spanish side after the departure of Neymar in a €222 million move to Paris-Saint Germain.
Juventus were drawn into Group D with Barcelona during the Champions League draw on Friday, with Olympiacos and Sporting CP also in the group.
While Juve made it to the Champions League final in 2016-17 - eventually losing to Real Madrid - Marotta is not worried about facing a "weakened" Barcelona in this year's group stage.
"Every group has its dangers and it's important that you are in form when you play those games, but Barcelona have weakened now that they have lost Neymar, even if they are still dangerous," he told Mediaset.
"We'll have to see how they replace [Neymar]," Marotta said, "but they are bound to have a quality team."