The Argentine attacker recently joined the Italian club following a difficult 20-month spell with West Ham United where he never became a first choice player.
In the wake of his La Viola debut, which came as a second-half substitute in the weekend's win over Torino, Zarate spoke of his time at Upton Park where he was constantly played out of position following his move from Velez Sarsfield in May 2014.
"It's a good chance for me to get back on track. In England, it was good because English football is enjoyable, but I wasn't too comfortable with my role at the club and that's why I decided to come here.
"I prefer to play in a free, attacking role, one that allows me to roam. I've already spoken with (Paulo) Sousa and he has assured me I'll have that."