On April 1, 2018, Tanaka pitched his debut game against the Orix Buffaloes as a relief pitcher.[2] In 2018 season, he pitched in 10 games.
In 2019 season, Tanaka hurt his right shoulder in spring training and spent 4 months in rehabilitation.[3] And he pitched only one game.
In 2020 season, Tanaka hurt his right elbow in spring training and spent the season in rehabilitation. As a result, he had no chance to pitch in the Pacific League.[4]
On June 27, 2021, Tanaka pitched in the Pacific League for the first time in two years against the Tohoku Rakuten Golden Eagles.[5] In 2021 season, he finished the regular season with a 18 Games pitched, a 0–0 Win–loss record, a 2.16 ERA, a one Holds, and a 14 strikeouts in 16.2 innings.
In 2022 season, he injured his right shoulder in the preseason game on March 20, and the effect delayed his start in the Pacific League on August 14.[6]
He finished the regular season with a 5 Games pitched, a 0–0 Win–loss record, a 0.00 ERA, a one Holds, and a 6 strikeouts in 5 innings.
Hokkaido Nippon-Ham Fighters
On January 12, 2023, Tanaka was traded to the Hokkaido Nippon-Ham Fighters as compensation for Kensuke Kondo, who exercised his right to free agency and moved to the Fukuoka SoftBank Hawks.[7]