The Italian striker's representative stated that a transfer to the San Paolo is a possible scenario and admitted that the player may even be sold on the cheap
The 25-year-old is widely expected to leave El Madrigal in the summer despite the fact that he is still nursing a knee injury as the Yellow Submarine are desperate to raise funds after being relegated to Segunda Division.
Napoli have long been credited with an interest in the Italy international, and his representative believes that a summer transfer is possible.
"I cannot exclude the possibility of a move to Napoli," Pastorello told Radio Kiss Kiss Napoli. "But he currently is a Villarreal player, that is for sure.
"But the market is open and we have not yet seen its true potential. I cannot rule out a move to Napoli, or anything for that matter.
"We are looking around for the best solution that can be shared with Villarreal. Giuseppe will return to action in February and it is normal that his market will accelerate in the last two weeks of August."
Rossi's representative then admitted that the Partenopei could sign the player at a cut-price, but stated he expects some performance-related clauses to be included in the deal.
"It could take as little €10 million (£7.8m) to sign him, but that may also not be enough," Pastorello noted.
"To sign Rossi, any fee could be enough, but then I believe that Villarreal want an assurance that if he returns to being a player who can score 30-35 goals a season, his valuation from last summer is guaranteed again.
"I think that there will be a fixed amount in the deal, but also some bonuses. But Villarreal's president will be the one to decide his price."