The Chile midfielder has been linked with a summer move to the Premier League club as new manager Louis van Gaal looks to strengthen his squad.
But Vidal, who has already ruled out a move to Old Trafford and is keen to hold talks over a new deal with Juve, remains a key part of the Serie A club’s plans.
Marotta told a press conference: “Arturo signed a contract extension last season because there was a mutual desire to continue our relationship.
“There is no reason for him to leave.
“I can confirm Vidal is happy to be with us and there’s no reason for alarm. Nobody can doubt the quality of the player, nor how strong his bond is with Juventus."
And Allegri added: “Vidal? I am not worried that we will lose him.
“The club are strengthening an already competitive group. I’m really happy.
“We will need a striker. Strengthening a club like Juve is not easy but the officials are doing good things.”
While confirming that Juve were in the market for a new forward, Marotta has ruled out a move for former Chelsea man Samuel Eto’o.
He added: “Eto’o? We have never thought about him.”