On the 14th, Nippon-Ham announced that they had reached an agreement on a contract with former Blue Jays infielder Rodolfo Castro. He will wear number 6 jersey. Castro commented through the team, "I would like to express my sincere gratitude to everyone involved with the team for giving me the opportunity to play in Japan. I am very much looking forward to being able to play in a country filled with passion for baseball. I will do my best to be a force for the team. The Fighters fans, let's fight together."

Castro, a native of the Dominican Republic, made his major league debut with the Pirates in 2021. He played in the majors until 2023 as a right-handed hitter infielder playing second base, third base, and shortstop. In 2023, he played in a career-high 92 games for the Pirates and Phillies. In his 194 major league games, he hit 22 Home Run, had 59 RBI, and a batting average of .219.

Last season, he played in the minor leagues for the Phillies, appearing in 134 games in Triple-A with 19 Home Run, 82 RBI, a batting average of .235, and 18 stolen base bases. In his minor league career, he appeared in 656 games with 90 Home Run, 380 RBI, a batting average of .243, and 50 stolen base.

Acting GM Kida commented, "He signed with the Pirates at the age of 16 and made his MLB debut at the young age of 21 in the 2021 season. He was a switch hitter until the 2024 season, but has switched to right-handed hitter since the 2025 season. He plays energetically, is aggressive and powerful, so I think he will contribute to improving the team's scoring ability. He is a utility player who mainly plays short stop, second baseman and third base, and also has experience playing center fielder. He has a strong arm and good running ability, so he is an exciting player to watch."