Stricken Rossi may still leave Villarreal
Rossi is currently recovering from a cruciate knee ligament injury and is not expected to return until next year.
Villarreal's relegation from La Liga means they are likely to lose a number of their key assets before the start of the new season.
Despite the front-man's injury, his representative Federico Pastorello believes Rossi may still secure a move during the transfer window.
"We are looking around to find the best solution that will be shared with Villarreal," Pastorello told Italian radio station Radio Kiss Kiss.
"Giuseppe will return in February, and it is normal that the market can be accelerated in the last fortnight of August.
"Cost? Less than €10 million, but I guess there will be a contract where there will be a fixed base and a very big portion in add-ons."
Napoli are believed to have shown an interest in Rossi in the past, and Pastorello added: "Napoli? I do not exclude the transfer of Rossi to the club of [Napoli president Aurelio] De Laurentiis.
"I cannot exclude this possibility. But now he's a football player for Villarreal, that's for sure. The market is open."