Marotta revealed the 44-year-old is unhappy about being repeatedly asked for his take on Gennaro Gattuso's current situation.
The former AC Milan midfielder is currently under investigation for alleged involvement in match-fixing, allegations he strenuously denies.
Marotta told juventus.com: "I think one of the club's duties is to support the manager's professionalism, allowing him the most serenity possible.
"He's saddened because every time the betting scandal is spoken about his name is brought up, despite the fact that he's already paid for a dismissed charge.
"As far as he's concerned it's a topic that is consigned to the past and his decision to not speak about it should be respected."
For breaking stories and all the great banter like us on Facebook: facebook.com/tribalfootball