joinedAmericanLeague

Given a predicate that represents a relationship or action between entities, generate a one-sentence description explaining its meaning.  
# Instructions
Focus on describing the relationship, not the entities themselves. 
# Response Format
Begin the description with \' Indicates...\'

Predicate: joinedAmericanLeague

Indicates that an entity became a member of the American League, typically by entering or being admitted to that sports organization.