Beckham to Leave U.S., Having Changed Business of American Soccer

For one thing, his arrival made the league adopt a light take on a European-style, free-market rule, setting it apart from other American leagues and giving it a foothold in the global market for soccer talent: "To offer contracts large enough to attract the likes of Beckham, MLS created a designated player rule — which quickly became called the Beckham Rule — that allowed teams to sign as many as three players whose contracts would count only partially against the league's meager salary cap."