The Chilean is expected to extend his existing contract for a further two more years and is set to earn around €5 million a year while Marotta also says Inter can win Serie A
The 26-year-old is expected to extend his existing contract, which expires in 2016, for a further two more years, with him set to earn around €5 million a year.
Vidal has emerged as a rising star at the club since joinng from Bayer Leverkusen in 2011 and has caught the eye with some impressive performances both in Serie A and the Champions League.
"Vidal arrived in Turin and the move was met with some scepticism, but he has done very well and now he should be rewarded," Marotta told Tuttosport.
"There have been big clubs in Europe interested in him but in the coming weeks, his contract will be prolonged and economically adequate."
Meanwhile, ahead of the Bianconeri's clash with Inter in next Saturday's Derby d'Italia, Juve's director general believes the Nerazzurri can be title contenders and says Walter Mazzarri is the right man for the club.
"It will be a tough match for us, it will be important to determine our quality but also the quality of our opponents, who I think can compete for Scudetto," he added.
"I would be happy if we lose this and break our 'days at the top of the table' record if at the end of the season we will win the Scudetto.
"And I would be even happier if we beat Inter and win the Scudetto aswell. But I know Mazzarri very well as I worked with him, and I'm sure that Inter will play very well good this season."