Napoli are preparing to beat Arsenal to the punch and lodge a summer offer for Olympique de Marseille defender Nicolas N’Koulou.The Cameroonian player is expected to leave the south of France club this summer and despite having a poor season is still regarded as a player that will generate a decent transfer fee.The 24-year-old could be available for around 10 million, according to reports in Tuttosport, and Napoli are set to make a swift move.The Neapolitan side are looking to add several defensive recruits this summer and have also been looking at Arsenal’s Thomas Vermaelen.N’Koulou is just one of a number of stars said to be on their way out of Marseille at the end of the season as new boss Marcelo Bielsa is tasked with overhauling the squad.Marseille are set to finish well outside the European places some and with two games remaining are 27 points behind leaders Paris Saint-Germain.