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.
However, Spalletti is adamant the 27-year-old will not be leaving the club.
"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."
The Italian also ruled out a move for Benfica striker Oscar Cardozo, while also questioning why the Portuguese side would be willing to listen to offers for the Paraguay international.
"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."
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