Miyaichi, 19, is currently on loan at Bolton where he is enjoying a successful spell with two assists and a goal frmo eight appearances and Walcott believes that's a sign of his development which should see him become a Gunners regular next season.
Speaking to Arsenal's official website, Walcott praised his young colleague and believes that the Japanese teenage sensation will be the bane of full backs next season.
"Ryo has done very well at Bolton," Walcott commented, "The way he is playing, there are full backs out there now who are thinking, ‘I don't want to play against him this week'."
The England international also feels that Miyaichi has coped well with Bolton in terms of non-footballing matters - he was on the pitch when Fabrice Muamba collapsed at Tottenham.
"It is hard for such a young kid to go there and do what he is doing, showing no fear with everything that happened at Tottenham [with Fabrice Muamba]. It is hard and it has probably hit him definitely," Walcott said.
"He will be a better person for it, a better player and I can see him coming back here next year and playing a lot more regularly."
Arsenal's previous loanee to Bolton Jack Wilshere nailed down a first team spot at the Emirates when his loan spell completed.