On January 16, 1970, the seven-time Golden Glove-winning center fielder Curt Flood of the St. Louis Cardinals files suit in a New York federal court against Commissioner Bowie Kuhn, the presidents of the American and National Leagues and all 24 teams in the Major League Baseball (MLB) organization.

After the Cardinals traded Flood to the Philadelphia Phillies in October 1969, Flood wrote a letter to Kuhn in late December, protesting the league’s player reserve clause, which prevented players from moving to another team unless they were traded. Kuhn denied Flood’s request to be made a free agent, and Flood decided to sue. In Flood v. Kuhn, the historic case that followed, Flood argued that the reserve clause violated antitrust laws and violated the 13th Amendment, which barred slavery and involuntary servitude.

Flood was not the first player to challenge the reserve clause, but he was certainly the most prominent, and stood to lose the most. In his 12 seasons with the Cardinals, he batted an average of .293, and he was paid $90,000 in salary for the 1969 season. He was also only 31 years old, at the peak of his career. After a U.S. district court judge rejected Flood’s claim in August 1970, the case went to the U.S. Supreme Court. Despite the support of such great players as Jackie Robinson, Flood suffered when no active players agreed to testify on his behalf, and the court ruled against him in a 5-3 decision in 1972.

By that time, Flood’s career was over. His lost battle turned into an eventual win for the players, however. Major League Baseball agreed to federal arbitration of players’ salary demands in 1973, and in 1975 an arbitrator effectively threw out the reserve clause, paving the way for free agency in baseball and all professional sports.