A malfunctioning aeroplane has delayed Uruguay international Edinson Cavani on his return from World Cup qualifying matches against Paraguay and Chile, meaning Mazzarri faces an anxious wait to see if his 27-goal forward arrives at the Stadio Olimpico in time.
Napoli are chasing down Juventus' nine-point lead at the top of Serie A and Mazzarri knows the Old Lady's city rivals present a serious obstacle under the management of veteran coach Giampiero Ventura.
Referring to Cavani, he told sscnapoli.it: "He's still travelling. We're well aware of the difficulties he had with the flight. I'll meet him and talk to him directly in Turin.
"They are absolutely one of the most difficult opponents, especially at this time. They have a quality squad and a coach I respect for always giving a strong identity to his teams.
"Their numbers speak for themselves - they are going on a journey and the ships have already launched.
"We will need to play a great game and our mentality is to win every single match so we can keep our high position in the league table.
"Il Toro know how to shut a game down and they have a variety of tactical approaches at their disposal. We will have to be at our best while expressing ourselves at the highest level."
Goalkeeper Morgan De Sanctis, who announced his international retirement after Italy's game in Malta, and defender Hugo Campagnaro are confirmed absentees while midfielder Valon Behrami faces a late fitness test.
"(Alessandro) Gamberini, (Paolo) Cannavaro and (Miguel) Britos will play in defence and I will decide on the rest tomorrow," Mazzarri added.
Midfielders Matteo Brighi and Valter Birsa miss out for Torino through injury, while winger Alessio Cerci should line up after making his Italy debut this week.
The Granata's results may have levelled out in recent weeks but a 10-point gap above the relegation places virtually guarantees Ventura's men a second straight season in the top flight.