On the 24th, Seibu announced that they have re-signed pitcher Takeru Sasaki and player Koichi Okumura as development players for next season. Sasaki's number will be 115 and Okumura's will be 116.

Sasaki joined the team as the second pick in the 2020 draft, pitching in 37 games in his second year in 2022 and 21 games in 2023, boasting outstanding stability with an ERA of 0.87, but underwent Tommy John surgery in August of that year. He was signed to a development contract that offseason, returned to action this season, and returned to the regular roster in June. He pitched in 15 games, but was released at the end of the season.

Okumura joined the team as the sixth pick in the 2023 development draft. In his first year, he was registered as a regular player in June of last season and played in 45 games, but has not played in the first team this season. In the farm team, he played in 36 games with a batting average of .195. He was released from the roster after the end of the season.