In South Korea, players belong to professional baseball teams conclude player contracts according to the baseball rules of Korea Baseball Organization in the uniformed agreement form. The uniformed agreement form has been revised several times to have a total of 34 articles and space for signature presently. Court rulings rightfully regard that the uniformed agreement forms are subject to the baseball rule which functions as a court of professional baseball league. In discussing about the equal footing with baseball teams in athlete agreements, a foothold will have to be established to protect players’ rights and interests effectively in terms of the baseball rule legal nature and standardized terms regulation act. The legal nature of professional baseball payers’ agreements are subject to the employment contract, subcontract, and delegation contract among the 15 standard agreement forms regulated by the civil code as well as other mixed regulations including individual laws such as labor standard act and Standardized Terms Regulation Act. When the Standardized Terms Regulation Act is applied to professional player contracts, it is found that the teams have abused their position and made unfair contract terms to limit players’ rights and interests. The use of collective agreement for professional baseball players is discussed by many scholars recently pursuant to the Trade Union and Labor Relations Adjustment Act. Sports agent scheme is continuously considered in the legal terms. For the development of South Korean sports industry, such efforts are underway.