The Seibu Lions announced on the 7th that Shuta Tonosaki will remain with the team without exercising his international free agent rights.

Tonosaki commented through the team, "I have decided not to exercise my free agency rights and will play for The Lions again next season. I want to refresh my mindset for the coming season and work hard to be an asset to the team. This season, the team finished in second place and advanced to the Climax Series, but we fell short of the championship. Next season, I will fulfill my role, leverage the experience I have gained so far, and do my absolute best to contribute to the team's championship victory. To all the fans, I ask for your continued warm support."

Tonosaki joined the Seibu Lions as the third-round draft pick in 2014. In his third year, 2017, he played in 135 games and established himself as a regular with a .258 batting average, 10 Home Runs, 48 RBI, and 23 stolen bases. The following year, 2018, he played in 119 games and contributed to the league championship with a .287 batting average, 18 Home Runs, 67 RBI, and 25 stolen bases. In 2019, he played in all 143 games and became a key figure in the team's consecutive league titles with a performance of a .274 batting average, 26 Home Runs, 90 RBI, and 22 stolen bases.

This season, he appeared in 35 games and recorded a .167 batting average, 2 Home Runs, and 9 RBI, which was the fewest number of games played since turning professional.