Contrary to the organization name, NABBP members were clubs, not individual players. Generally the clubs joined the association and retained membership by sending delegates to the annual convention, usually in the December preceding each season (the ancestor of modern Major League Baseball's so-called Winter Meetings). Membership mediated by state associations was introduced only after ten years; then dozens of clubs from a distant state could join and remain in the NABBP by organizing a state association whose delegates would participate in the national meeting.