The on-loan winger, who joined the Latics from Arsenal last summer, has been sidelined for three months with an ankle injury.
But the 20-year-old, who last played for Roberto Martinez's men in November, is relishing his comeback at the Madejski Stadium.
The Japan international told the club's official website: "It will be a big relief to get back because it has been quite a tough time to be sat on the sidelines.
"I had a groin injury at first when I was with the national team last year.
"That injury put me out for a few months and then I came back in the game against Liverpool at Anfield and after that game I picked up an ankle injury which has made things frustrating.
"I trained after that game and it made my ankle worse but I can learn many things from this injury".
Wigan currently sit second-bottom of the Premier League, two points behind 18th-placed Reading.
Miyaichi added: ""It is important now for us to win as many games as possible because we are desperate to stay in the Premier League.
"I want to be able to help the team in achieving safety in the Premier League and it will be great to show the supporters what I can do once I am back."