Rossi is in the squad, but it seems unlikely he'll be able to take part.
"I spoke to him yesterday and I think his presence at the San Paolo can be definitively ruled out," agent Federico Pastorello told Radio Kiss Kiss.
"It's impossible to recover in time for Tuesday, save for miracles, and his injury will probably be worse than previously thought.
"Villarreal brought him along with the squad, but unfortunately he won't be able to play."
Over the summer President Aurelio De Laurentiis repeatedly stated he wanted to bring Rossi to Napoli, either this year or in the future.
"As far as we know, the two clubs contacted each other, but did not speak directly with us," added the agent.