By FOX Sports staff
Nagai spent the 2012/13 season on loan at the NIB Stadium scored two goals in 17 appearances for Glory and helped them reach the Finals Series, where they were eventually eliminated at the first hurdle by Melbourne Victory.
The 22-year-old had initially returned to Cerezo at the conclusion of the last campaign, but will now be back in Perth colours for another year after the club confirmed they have re-signed him for 2013/14.
Glory manager Alistair Edwards expressed his delight at the securing Nagai's services and believes his versatility will be crucial to the team's prospects.
"I'm thrilled that we've managed to bring Ryo back to the club for the whole of next season," he said on the Football Federation Australia's official website.
"Ryo finished last season extremely well and became very much a crowd favourite.
"From the time myself and [assistant manager] Gareth [Naven] came in, he improved with each game.
"He's very versatile and can play wide right or left and also down the middle, and he's so well thought of here at Glory."
Nagai, who is Glory's second signing of the week following the capture of Jamie Maclaren from Blackburn, has arrived in Perth from Japan and will join his team-mates for pre-season training on Friday.