The Japan winger is yet to make an impact at Arsenal after spending his time away on-loan over the past two seasons.
"I have great hopes for Ryo because he has the traditional Japanese qualities," Wenger told Arsenal Player. "Japanese players technically have a very good touch, they are mobile, agile, a bit lightweight but they move well. It's usually a player that has a great attitude towards the team.
"Ryo has a fantastic attitude for sure. He has just come out of rehab after a big knee injury, and the physios have told me they have never known an attitude like it. So he has those qualities, and as well he is tricky, has great pace, and works very hard.
"He has to learn to become mature tactically - shrewd tactically - but all the rest, he has."