Silverman (plaintiff), the General Counsel for the National Labor Relations Board (NLRB) and the Major League Baseball Players Association (PA), petitioned the district court for an injunction barring the Major League Baseball Player Relations Committee (PRC), the collective-bargaining representative for the major-league clubs, from eliminating the free-agency system and salary arbitration. Under the basic agreement between the major-league club owners and the players, the free-agency system allowed players who had played six major-league seasons to set their wages directly with individual clubs. Reserve players, i.e., players who had less than six years of experience, signed a standard agreement called a Uniform Player's Contract (UPC). Players with more than three but less than six years of experience were eligible for salary arbitration. In the salary-arbitration process, if a player and owner could not agree to a salary, the parties each signed the UPC and submitted a salary figure to an arbitrator. The arbitrator then determined the player's salary based on evaluation criteria set forth in the basic agreement. Additionally, players of any experience level were eligible for arbitration of salary disputes if both parties consented. The NLRB contended that the PRC had committed an unfair labor practice because they undermined the collective-bargaining process. The PRC did not dispute that it had changed the free-agency system and eliminated salary arbitration, but the PRC argued that issues related to the free-agency system and salary arbitration were permissive, not mandatory, subjects of collective bargaining.