Happy 10th birthday to the SABR/Baseball-Reference Encyclopedia. Thanks to all those who have contributed and welcome to any who wish to contribute.
Promotion and relegation
From BR Bullpen
Promotion and relegation systems are rare in baseball, though common in other sports. They are found in many European leagues such as Hoofdklasse and Division Elite (and formerly Serie A1). A promotion and relegation system is one in which teams can be bumped from the top league to a minor league or promoted from a minor league based on performance over time. As a result, membership in the top circuits in those countries is far more fluid than in the US, Japan, Cuba or South Korea.