Vidal has become a key man for Juventus since joining the Turin club in 2011 from German side Bayer Leverkusen.
The 26-year-old midfielder has helped Antonio Conte's win back-to-back Serie A titles, scoring 25 goals in his time with Juventus.
Marotta revealed that Real made a close-season approach for Vidal, and feels that the Chile international is worthy of the reported €100 million fee that the Liga club paid to take Bale from Tottenham to the Bernabeu.
"If Bale is worth €100 million, then the same goes for Vidal," he told Mediaset.
"Real Madrid expressed an interest this year, but selling him is out of the question so the interest ended there."
Marotta was also quick to praise French midfielder Paul Pogba, who has established himself as an integral part of Conte's side.
"We can say the same about Pogba (as Vidal)," Marotta added.
"He's a solid element of the team and we've turned down all the offers we've received for him.
"He's exploded in an almost unexpected way, so compliments to the lad but also to (Antonio) Conte who has managed to get the best out of him.
"If he confirms his status at the highest of levels, as we obviously hope he will, then this should be recognised with an increased salary."
