However, Turkish midfielder Hamsik insists that his side are still in with a shot of achieving their main targets for the season.
"We are on course to reach all our objectives," Hamsik told Radio Kiss Kiss. "Champions League qualification, the Europa League and the Coppa Italia.
"We are all on a journey together and we will continue to grow."
Napoli have won just one of their last five matches in all competitions, and are back in league action on Saturday night when they face AC Milan.