The goalkeeper enjoyed a season on loan at the Serie A side, but says he has to head back to Anfield ahead of the new season amid ongoing speculation regarding his future.
The Spaniard spent 2013-14 on loan in Naples, and impressed for Rafael Benitez's side as the team won the Coppa Italia and finished third in Serie A, but is due to return to Anfield ahead of next season.
However, with Simon Mignolet established as Liverpool's first-choice keeper, Reina is open to the idea of leaving the club permanently - with Napoli one possible destination.
"I believe that the possibility is there," he told Radio Onda Cero. "In Naples I've been very good this year, where I feel well liked and where there is a plan on the table that makes you dream.
"I never discarded the idea of staying in Naples.
"I have a contract at Liverpool and I have to go back there, but there are also chances that [I will] go away again."