U（27）
- Active Players
- U
U
- 69 Pitcher
- Uchi, Seiryu
- Tohoku Rakuten Golden Eagles
- 36 Infielder
- Uchida, Yasuhito
- Tohoku Rakuten Golden Eagles
- 7 Infielder
- Uchikawa, Seiichi
- Tokyo Yakult Swallows
- 40 Pitcher
- Uchima, Takuma
- Tohoku Rakuten Golden Eagles
- 33 Catcher
- Uchiyama, Souma
- Tokyo Yakult Swallows
- 025 Catcher (*)
- Uchiyama, Taishi
- Tokyo Yakult Swallows
- 013 Pitcher (*)
- Udagawa, Yuki
- ORIX Buffaloes
- 51 Outfielder
- Uebayashi, Seiji
- Fukuoka SoftBank Hawks
- 62 Infielder
- Ueda, Kai
- Hanshin Tigers
- 203 Pitcher (*)
- Ueda, Kotaro
- Chunichi Dragons
- 95 Catcher
- Ueda, Shota
- Chiba Lotte Marines
- 20 Pitcher
- Uehara, Kenta
- Hokkaido Nippon-Ham Fighters
- 64 Pitcher
- Uema, Towa
- Saitama Seibu Lions
- 0 Infielder
- Uemoto, Takashi
- Hiroshima Toyo Carp
- 48 Infielder
- Ueno, Kyohei
- Hokkaido Nippon-Ham Fighters
- 38 Outfielder
- Ugusa, Koki
- Hiroshima Toyo Carp
- 65 Catcher
- Umebayashi, Yuki
- Hokkaido Nippon-Ham Fighters
- 2 Catcher
- Umeno, Ryutaro
- Hanshin Tigers
- 38 Pitcher
- Umeno, Yugo
- Tokyo Yakult Swallows
- 18 Pitcher
- Umetsu, Kodai
- Chunichi Dragons
- 62 Catcher
- Umino, Takashi
- Fukuoka SoftBank Hawks
- 120 Pitcher (*)
- Une, Takamasa
- Hiroshima Toyo Carp
- 98 Infielder
- Urena, Estamy
- Yomiuri Giants
- 65 Pitcher
- Urushihara, Taisei
- ORIX Buffaloes
- 30 Catcher
- Usami, Shingo
- Hokkaido Nippon-Ham Fighters
- 27 Pitcher
- Utsumi, Tetsuya
- Saitama Seibu Lions
- 15 Pitcher
- Uwasawa, Naoyuki
- Hokkaido Nippon-Ham Fighters