There are three recommended divisions of play for Jr. RBI (based on league participation numbers): ages 5 to 7, ages 8 to 10 and ages 11 to 12. Each playing level has its own set of age-appropriate rules. In divisions with players ages 5 to 10, the emphasis is on teaching the fundamentals of baseball and making the game fun. Divisions for players ages 11 to 12 may be used as an introduction to competitive baseball and softball.

Player safety is a priority for Jr. RBI. For all baseball programs, the playing rules highlight the importance of protecting pitchers’ arms with a pitch count, which is used to track the stress on young players’ developing bodies. For softball programs, playing rules highlight the introduction to the game at the earliest ages.