The Brazil international has been absent for the Russian side since their 3-0 victory over Anzhi Makhachkala on August 17 with a hamsting injury, but that has not stopped speculation around his future.
He had been linked with moves to Chelsea and Monaco during the close-season, and Andre Villas-Boas' side are the latest team said to be preparing a bid as they prepare for Gareth Bale's expected departure to Real Madrid.
"Hulk is not for sale," he said ahead of Zenit's UEFA Champions League play-off second leg with Pacos Ferreira.
"Hulk recovers quickly, but as I said before, the situation must be evaluated step by step.
"We don't know the exact date of his recovery.
"He's a unique player because he has a large muscle mass, but his recovery is going well. Our doctors will assess the situation, and very soon we'll know when he`ll be back.
"And another thing: Hulk is not for sale."
"Yes, we know him, and played against him, but we're not interested in him," he added. "And I don`t understand why Benfica wants to sell him."
