United and Arsenal were linked with the Italy forward during the January transfer window, and that interest has continued following the end of the season.
Petrachi insists Torino are desperate to keep the 26-year-old attacker at the Serie A club if possible - but seemingly admits they would be powerless to stop him leaving if that's his wish.
"We want to keep Alessio because we don't need to sell at this moment in time," Petrachi said as reported by the Daily Express.
"That was also the case for Immobile [who joined Borussia Dortmund] but the will of the player is important."
Cerci has taken his place in Italy's World Cup squad and is hoping to start against England on Saturday evening although he may miss out. He hit 13 Serie A goals last season, and has played his way into contention for his country.
That form last term attracted the interest from the likes of Arsenal and United, and Cerci is only under contract at Torino until the summer of 2016.
Arsenal are hoping to sign another attacker this summer, although Cerci is not thought to be one of their main transfer targets. United meanwhile need reinforcements across the squad, and Louis Van Gaal is expected to bring several of his Dutch squad to Old Trafford following the World Cup.