On the 28th, Nippon-Ham announced that they had reached an agreement for pitcher Kohei Arihara to join the team.

Through the team, Arihara commented, "I am very happy to have been associated with The Fighters, a team in Hokkaido, where my professional baseball career began. Under the guidance of Manager Shinjo, I would like to swing my arm with all my might and contribute to the team by pitching as long as possible, even if it is just one inning."

Arihara joined Nippon-Ham as the first pick in the 2014 draft, winning eight games in his first year in 2015 and earning the Rookie of the Year award. He earned his first career Most Wins award in 2019, and in the offseason of 2020, he used the posting system to challenge the majors. After two years with the Rangers, he joined Softbank Hawks in 2023, recording 10 wins in his first year, and last season he won the Most Wins title (14 wins), his first since his time with Nippon-Ham. He was instrumental in the team's first league championship in four years. This season, he also earned the most wins (14 wins), pitching 26 games and 175 innings, finishing with 14 wins and a 3.03 ERA.