Like Dr. Martin Luther King Jr., athletes have dreams too, but theirs, for the most part, are of excellence and dominance over their opponents, and of their chosen sport.

Throughout the years, there have been various athletes who have, like Dr. King, been selfless, put it all on the line, defined themselves beyond the field, beyond the court, beyond the field. Former NFL quarterback Colin Kaepernick, still trending since first taking a knee during the national anthem at a San Francisco 49ers game in 2016, might immediately come to mind, but in 1968, six months after Dr. King was assassinated, the silencing of the greatest defender of humanity that we’ve ever known, American track athletes Tommie Smith and John Carlos, gold and bronze 200 meter winners during the Summer Olympic Games in Mexico City, Smith setting a world-record of 19.83 seconds, sparked outrage nationally and abroad when each of them, wearing a black leather glove, raised their gloved fist, the Black Power salute, with heads bowed while receiving their Olympic medals as the national anthem played.

There were no hash tags, but like Kaepernick kneeling, it ignited anger, it was controversial, it trended. They set it off. Front page news. Smith and Carlos were the Colin Kaepernick of their time. For Black America, it was revolutionary, an iconoclastic statement to this day.

One year later, after baseball season ended, three-time All-Star Curt Flood, a two-time World Series champion and seven-time Gold Glove winner, refused to abide by a trade agreed on by the St. Louis Cardinals and the Philadelphia Phillies sending Flood to Philadelphia. This defiance initiated the start of what is now known throughout sports as free agency, a player’s ability to negotiate or sign with another competing team.

Until Flood took a stand, a player on a team could only be traded, reassigned, sold or released at the discretion of their team. The rights to a player were retained by the team at the contract’s expiration. It kept players beholden for life to the team that originally signed them even after the contract expired. It was known as the Reserve Clause. A player didn’t have the freedom to change teams unless given an unconditional release. The only leverage that a player such as Flood and others had was to hold out at contract time, refuse to play unless their conditions were met.

In a letter to Bowie Kuhn, the commissioner of baseball in December 1969, Flood stated, “I do not feel that I am a piece of property to be bought and sold irrespective of my wishes.” Flood wanted the right to consider offers, and to negotiate with other interested teams once his contract expired.

Although it took some time, the Reserve Clause was abolished in 1975. The Curt Flood Act of 1998 was also the outcome of his actions, establishing federal antitrust protection for Major League Baseball players that exists for other professional athletes. Flood’s actions are also responsible for the 10/5 Rule, which states that once a player has played for a team for five straight years, and played in Major League Baseball for 10 years, the player has to give the team their permission to be traded.