Curt Flood took MLB to the U.S. Supreme Court regarding the legality of the reserve clause, and although he lost the case, the high court put baseball on notice that the practice was a restraint of trade. Here's is Flood's letter to Commissioner Bowie Kuhn, announcing Flood's desire to be a free agent.
Mr. Bowie K. Kuhn
Commissioner of Baseball
680 Fifth Avenue
New York, New York 10019
After twelve years in the Major Leagues, I do not feel I am a piece of property to be bought and sold irrespective of my wishes. I believe that any system which produces that result violates my basic rights as a citizen and is inconsistent with the laws of the United States and of the sovereign States.
It is my desire to play baseball in 1970, and I am capable of playing. I have received a contract offer from the Philadelphia Club, but I believe I have the right to consider offers from other clubs before making any decisions. I, therefore, request that you make known to all Major League Clubs my feelings in this matter, and advise them of my availability for the 1970 season.
Sincerely Yours, Curt Flood.
This story was not subject to the approval of Major League Baseball or its clubs.