expired. In a landmark 1922 Supreme Court decision, Federal Baseball Club v. National League, baseball was granted a special immunity from antitrust laws. Despite the advent of free agency in 1976, which led many to predict the demise of the farm system, it still remains a strong component of a winning baseball strategy. Ice hockey The teams of the National Hockey League also have their own farm teams in the American Hockey League (AHL). For example, the Cleveland Monsters are the farm team for the Columbus Blue Jackets. Additionally, NHL teams have affiliates in the ECHL, although the terms of the most recent CBA (expired in 2012) prohibited ECHL players from being recalled to the NHL or being sent down to that league without being assigned to the AHL first; thus, ECHL teams are de facto affiliated to their respective NHL-partner's farm team in the AHL. Although some NHL franchises own their AHL and/or ECHL affiliates, many AHL and ECHL franchises are independently owned, with ties to NHL franchises made through affiliation contracts. Unlike baseball, not all the players on the rosters of the minor league teams are owned by an NHL team. The AHL system recognizes two types of contracts: the two-way contract (generally the most common among NHL prospects), in which players can be sent back and forth between the NHL and AHL at will, and the standard contract, which binds the player to the AHL. The NHL teams have negotiating rights to AHL players on their farm clubs' rosters and can upgrade a player to a two-way contract if they so desire. Players can also be sent down to the AHL via the waivers system; if a player is not claimed by any team when placed on waivers, he is by default assigned to his previous team's AHL club. Association football Internal feeder teams In many clubs, there will be internal feeder teams. These may be age-restricted teams, such as an 'Under-18s' team, or an 'A team'. For example, in international association football, national teams also operate youth sides—see England national under-21 football team, for example. In the United States, some Major League Soccer teams previously had reserve teams in the MLS Reserve League. Later, all teams were nominally required to field a reserve team or an affiliate in a professional league operated by the United Soccer League—either the USL Championship, which occupies the second tier of