Evolution of NPB Roster Limits - How the Expansion from 25 to 31 Active Players Reshaped Lineup Tactics
NPB's active roster has long operated under a 28-player registration cap (with 25 players permitted to dress for a game). After the 2020 COVID-19 pandemic prompted balancing infection control with game operation, the cap expanded, and a 31-player roster has now taken hold. This evolution has reshaped bench tactics, the deployment of development-contract players, and the interplay with the farm system. We trace NPB's roster history from the regulatory side.