Vidal featured in 13 of Barca's 18 matches this season prior to Sunday's trip to Atletico Madrid, though just four of those appearances have been starts.
The Chile international this week vowed to leave Camp Nou next year should he fail to be given more minutes by Ernesto Valverde, despite having 18 months to run on his contract.
Inter have been tipped to move for Vidal, who worked with Marotta and head coach Antonio Conte at Juventus, but the Nerazzurri chief said his Barcelona deal must be respected.
"He is an important player on the world stage and both Conte and I are tied to him because of our great past together," Marotta told Sky Sport Italia.
"We have great considerations of him. I think a lot of teams would like to sign him, but unfortunately he's at Barcelona. However, thoughts can certainly be made."
Inter beat SPAL 2-1 on Sunday through a Lautaro Martinez brace to leapfrog Juventus at the Serie A summit.