Roma have confirmed that Mario Rui has completed a season-long loan switch to Napoli.
The 26-year-old has finalised his move after passing a medical with Maurizio Sarri's side.
Napoli will pay EUR3.75million for the initial deal and will be obliged to sign him outright for a further EUR5.5m fee if "certain sporting targets" are met, Roma said.
Mario Rui joined from Empoli last year but a cruciate ligament injury meant he was unable to make his debut until January in a 4-0 Coppa Italia win over Sampdoria.
He made a total of nine appearances in 2016-17.