On the 4th, Seibu Lions announced that they will be sending player Teruki Koga to the Japan Winter League 2025 starting December 6th.

Koga commented through the team, "I will be joining mid-season, but I hope to broaden the scope of my play by actively trying different things. This is a valuable opportunity to see, hear, and learn from the play and way of thinking of players from other teams, so I would like to use what I learn there to help me grow as a player. In particular, I will work hard to improve my batting so that I can return at even the slightest level."

Koga, a rookie drafted seventh, did not play in the first team this season, his first year as a professional, but instead played in 16 games for the farm team, batting .159 with Home Run and three RBI.