The is a system that allows players to be held for the purpose of training players separately from the 70 registered players under control of each team created in the fall of at Nippon Professional Baseball (NPB). It is akin to the practice squads seen in other sports.

Summary The system was established in 2005 to create an environment in which amateur players could gain playing experience after company-owned amateur baseball teams were folding following the economic recession of the Lost Decades. Players who are part of the system are considered "semi-controlled" in that they play for the team they are signed to but they are not a controlled player and thus their team doe not have exclusive rights to them.

The Developmental Player System include players drafted as rookies (e.g. Yusuke Kosai, Michitaka Nishiyama), foreign players signed as developmental players (e.g., Raidel Martínez, Liván Moinelo), players drafted as registered players under control but re-signed with a team as developmental players due to their abilities (e.g., Kenta Kurose), players who became free agents with their former team and signed with another team (e.g., Masaru Nakamura, Kouya Fujii), and players who were removed from the registration of players under control and re-signed as a developmental player as an injury rehabilitation assignment (e.g., Takuya Kuwahara, Hiroya Shimamoto). There is an argument that de-registering players who cannot play due to injury and re-signing them as developmental players will protect their careers; on the other hand, the use of the developmental players system, instead of systems like the Major League Baseball (MLB) Injured list, is criticized as contrary to the original intent of this system to develop and provide opportunities to amateur players. The oldest player to become a developmental player is Soichi Fujita, who signed in at the age of 39. The longest period as a developmental player was 's eight seasons (2011-) as of the season.

Regulations for Developmental Players

Player Rules Developmental players are not allowed to participate in official NPB games. However, up to five players per team per game are allowed to play in the Eastern League and Western League, the NPB's minor leagues. These minor league farm teams are considered a team's second squad. If a team as a large amount of developmental and minor league players, they may form a third squad and play in games against independent league teams (such as the Shikoku Island League Plus and Baseball Challenge League), corporate amateur teams, or university teams. The Fukuoka SoftBank Hawks's third squad plays more than 100 games a year. While there is a difference in contract between a registered players under control and a developmental players, unlike the relationship between players Major League Baseball and Minor League Baseball in North America, all NPB are players on the same team regardless of which squad they are on, and use the same practice facility and player dormitory. A Developmental Player System contract is for a maximum of three years. After this contract expires, the player can become a free agent once and sign with the same team again for a one year extension. After the fourth season, and each subsequent season, the NPB will announce the player's free agent status. This measure is intended to increase the player's chances of signing a registration of players under control contract, and during the free agent period, he can negotiate with other teams. For example, in 2019, Hiroki Hasegawa moved from the Fukuoka Softbank Hawks to the Tokyo Yakult Swallows. A one-year contract is also possible for a registered players under control to re-sign as a developmental player after a free agent announcement has been made. Players who have not been under contract for three seasons will be placed on the roster of pending developmental players, and other teams will not be able to negotiate with them. The minimum salary is ¥2.4 million and ¥3 million is paid as a preparation fee when drafted. However, since there is no cap on annual salary, some teams sign players at higher salaries, and players who are re-signed as developmental players from a registered players under control often maintain the salary level of a registered players under control. A developmental player's uniform number will be a three-digit number (e.g. 001, 101, or 201) in the numbers of other players and staff being one- or two-digits.

Regulations for teams that own developmental players The deadline for re-signing a developmental player to a registered player under control contract is from the end of the season to July 31st during the following season. However, teams are not permitted to change a player's contract status from a registered under control to developmental during the season. Developmental players can only be owned by teams with at least 65 controlled players on their roster by July 31 each eason, and teams with fewer than 65 controlled players cannot own them. However, if a team reports to the Executive Committee that it has re-signed a developmental player as a controlled player or acquired a new controlled player to bring the number of controlled players to 65 or more, and if this is approved, the team may retain the developmental player. There is no limit to the number of developmental players owned and how many a team has depends on the team's policy. For example, the Yomiuri Giants and Fukuoka SoftBank Hawks often have more than 30 developmental players, enough to field a third-level squad; conversely, the Hanshin Tigers tend to have only a few players. The Fukuoka SoftBank Hawks selected 14 new developmental players in the 2022 draft to implement a four-team system starting in the 2023 season.

Developmental Players Draft Meeting If the total number of players selected at the end of the Rookie Player Selection Conference has not reached 120, a Developmental Players Selection Meeting will be held with the participation of the teams that wish to participate.

Developmental players trade Article 11 of the Nippon Professional Baseball Developed Player Regulations states that a trade of a developmental player held by July 31 is allowed, but as of the 2022 season, there are no examples of such a trade.

Outcome

The developmental player system, which began in the 2005 season, has been successful in producing major players for each team (e.g. Yoshiki Sunada, Yuji Nishino). The Yomiuri Giants, who have been heavily utilizing this system since the beginning, have signed more than 50 developmental players as their registered players under control as of the 2022 season. The Fukuoka Softbank Hawks have also signed 40 developmental players as their registered players under control, and have produced players like Kodai Senga and Takuya Kai who have won league titles and awards and represented Japanese baseball on the national baseball team. The Hokkaido Nippon-Ham Fighters, which had been reluctant to acquire developmental players, drafted a player as a developmental player for the first time in the 2018 draft. In the 2022 draft, 51 players will be selected as developmental players, the largest number in history, and the acquisition of developmental players is a growing trend.

+ Holders of league titles and awards from developmental playersPlayer nameTeamenrollmentLeague Titles and AwardsShuta IshikawaFukuoka SoftBank Hawks2013 Draft.1× Pacific League winning percentage leader (2020)1× Pacific League the most wins Champion (2020)Pitched a no-hitter on August 18, 2023Takuya KaiFukuoka SoftBank Hawks2010 Draft.6× Pacific League Golden Glove Award (2017–2022)3× Pacific League Best Nine Award (2017, 2020. 2022)Raidel MartínezChunichi DragonsSigned in 2017.1× Central League Saves leader (2022)Tetsuya MatsumotoYomiuri Giants2006 Draft.1× Central League Rookie of the Year (2009)Liván MoineloFukuoka SoftBank HawksSigned in 2017.1× Pacific League Best Relief Pitcher Award (2020)1× Pacific League Holds leader (2020)Yoshifumi OkadaChiba Lotte Marines2008 Draft.2× Pacific League Golden Glove Award (2011, 2012)Yariel RodríguezChunichi DragonsSigned in 2020.1× Central League Best Relief Pitcher Award (2022)1× Central League Holds leader (2022)Kodai SengaFukuoka SoftBank Hawks2010 Draft.2× Pacific League strikeout leader (2019, 2020)1× Pacific League ERA leader (2020)1× Pacific League winning percentage leader (2017)1× Pacific League the most wins champion (2020)2× Pacific League Best Nine Award (2019, 2020)2× Pacific League Golden Glove Award (2019, 2020)Pitched a no-hitter on September 6, 2019Ukyo ShutoFukuoka SoftBank Hawks2017 Draft.1×Pacific League Stolen bases Leader (2020)Tetsuya YamaguchiYomiuri Giants2005 Draft.1× Central League Rookie of the Year (2009)3× Central League Best Relief Pitcher Award (2009, 2012-2013)

Current developmental player rosters Central League

PositionPlayerssource (:ja:井上剣也) (:ja:土生翔太) (:ja:森山暁生) (:ja:山浅龍之介)(:ja:中村奈一輝) (:ja:津田啓史)(:ja:石川大峨) (:ja:川上理偉)(:ja:三上愛介) (:ja:松原快)(:ja:伊藤稜) (:ja:アンソニー・マルティネス (:ja:川﨑俊哲)(:ja:ジーン・アルナエス) (:ja:山﨑照英)(:ja:スタンリー・コンスエグラ)(:ja:小船翼) (:ja:竹下海斗) (:ja:河野佳)(:ja:杉原望来) (:ja:安竹俊喜) (:ja:ネルソン・ロベルト)(:ja:竹山日向) (:ja:小宮悠瞳)(:ja:西濱勇星)(:ja:髙橋翔聖) (:ja:佐藤琢磨 (野球))(:ja:松本龍之介) (:ja:中川拓真)(:ja:根岸辰昇)(:ja:西濱勇星)(:ja:清水麻成) (:ja:金渕光希) (:ja:吉岡暖)(:ja:森下瑠大) (:ja:松本隆之介)(:ja:上甲凌大)(:ja:近藤大雅)(:ja:小笠原蒼) (:ja:清水詩太)(:ja:小針大輝)(:ja:冨重英二郎) (:ja:林燦) (:ja:堀江正太郎) (:ja:千葉隆広) (:ja:木下幹也) (:ja:園田純規)(:ja:松井颯) (:ja:田村朋輝) (:ja:吉村優聖歩) (:ja:富田龍) (:ja:森本哲星) (:ja:黃錦豪) (:ja:花田侑樹) (:ja:石田隼都) (:ja:石田充冴) (:ja:京本眞) (:ja:坂本達也)(:ja:中田歩夢) (:ja:村山源) (:ja:田上優弥)(:ja:竹下徠空) (:ja:北村流音) (:ja:相澤白虎)

Pacific League

PositionPlayerssource (:ja:秋山正雲) (:ja:永島田輝斗) (:ja:中山優人)(:ja:茨木佑太) (:ja:長島幸佑) (:ja:武内涼太) (:ja:チャリエル・ラドニー)(:ja:富山紘之進)(:ja:金田優太) (:ja:勝又琉偉)(:ja:谷村剛) (:ja:松石信八)(:ja:杉山諒) (:ja:髙野光海)(:ja:藤田和樹) (:ja:スティベン・アセベド) (:ja:宮里優吾) (:ja:河野伸一朗) (:ja:川口冬弥) (:ja:村田賢一) (:ja:津嘉山憲志郎) (:ja:相原雄太) (:ja:井﨑燦志郎) (:ja:岡田皓一朗) (:ja:澤柳亮太郎) (:ja:田中怜利ハモンド) (:ja:山崎琢磨) (:ja:熊谷太雅) (:ja:塩士暖) (:ja:長水啓眞) (:ja:内野海斗) (:ja:岡植純平) (:ja:佐々木明都) (:ja:飛田悠成) (:ja:ダリオ・サルディ)(:ja:大友宗) (:ja:牧原巧汰) (:ja:盛島稜大) (:ja:藤野恵音) (:ja:桑原秀侍) (:ja:広瀬結煌) (:ja:佐倉俠史朗) (:ja:中澤恒貴)(:ja:江崎歩) (:ja:山下恭吾) (:ja:西尾歩真) (:ja:大泉周也) (:ja:漁府輝羽) (:ja:重松凱人) (:ja:佐藤航太) (ホセ・オスーナ)(加藤大和) (:ja:松本遼大) (:ja:川勝空人) (:ja:澁谷純希) (:ja:安西叶翔) (:ja:日渡騰輝)(:ja:濵田泰希)(:ja:藤田大清) (:ja:山口アタル)(:ja:星野ひので) (:ja:寿賀弘都) (:ja:芦田丈飛) (:ja:上原堆我)(:ja:乾健斗) (:ja:前佑囲斗) (:ja:河内康介)(:ja:村上喬一朗) (:ja:河野聡太) (:ja:今坂幸暉)(:ja:清水武蔵) (:ja:大里昂生) (:ja:香月一也) (:ja:寺本聖一)(:ja:元謙太)(:ja:上間永遠) (:ja:宮澤太成) (:ja:斎藤佳紳) (三浦大輝) (:ja:濱岡蒼太) (シンクレア) (:ja:平口寛人) (:ja:川下将勲)(:ja:木瀬翔太) (:ja:正木悠馬) (:ja:野田海人)(:ja:新井唯斗) (:ja:今岡拓夢) (:ja:古賀輝希) (:ja:谷口朝陽)(:ja:金子功児) (:ja:福尾遥真) (:ja:フアン・コルニエル) (:ja:奥村光一) (ラマル) (:ja:安藤銀杜)(:ja:澤田遥斗) (オケム) (:ja:德山一翔) (:ja:松田啄磨) (:ja:中沢匠磨) (:ja:蕭齊)(:ja:水上桂)(:ja:島原大河)(:ja:岸本佑也) (:ja:前田銀治) (:ja:幌村黛汰)(:ja:大坪梓恩)

See also Nippon Professional Baseball List of current Nippon Professional Baseball team rosters Registration of players under control List of developmental players for the Nippon Professional Baseball (at Japanese-language Wikipedia)

References

External links Nippon Professional Baseball Agreement・Unified contract documents - Japan Professional Baseball Players Association Official site Nippon Professional Baseball public notice 2023 - NPB.jp Teams index - NPB.jp