The Denmark international has struggled to make his mark for the Italian giants since arriving from Tottenham Hotspur in January, managing just four goals and three assists in 38 appearances.
Eriksen has not scored or registered an assist in 12 outings this term, meanwhile, and has been strongly linked with a move back to the Premier League in recent weeks.
"Eriksen is on the transferable list," Marotta told Sky Italia. "He has struggled to settle into the squad, he is not functional to the squad. That's just an objective fact.
"That is not any insult towards his professionalism, there is no punishment, it's just a situation that has developed and it's only fair to give him the chance to go where he can play more regularly."
Eriksen is thought to be valued by I Nerazzurri in the region of £27m.