Curt Flood's refuses to be traded
On Oct. 7, 1969 the Cardinals traded Curt Flood to the Phillies for three players. The only problem? Flood refused to go. He forfeited his lucrative contract and demanded the commissioner declare him a free agent. MLB commissioner Bowie Kuhn declined, and Flood sued. Eventually his case went before the Supreme Court, where it was struck down. Free agency as we now know it did not begin until 1975, but it could not have happened without Flood laying the groundwork.