MLB players were terribly exploited by management until Miller came along.  Though it's just a game, the players are elite athletes at the apex of a huge pyramid of players.  The minimum salary was USD 6,000/year before Miller came along.

Marvin Miller was the Moses of MLB players. He freed them from the slavery of the reserve clause. Actually, I should say he was the Moses for all professional athletes. Every pro athlete should have a shrine to this man. He freed them from the bonds of slavery and led them to the promised land. "So let it be written, so let it be done."

These being the same players who refuse (to this day) to kick money back to the players that were not grand-fathered in? 

In response to EnchiladaT's comment:

How does their (alleged) greed invalidate Miller's actions or the players' right to earn a market wage?

A good attorney yes, but true American hero, hardly. Maybe to baseball players 

George Washington was an American hero.  Sgt Alvin York was an American hero.  Audie Murphy was an American hero.  Pat Tillman was an American hero.

 

Marvin Miller was an Attorney... 

 

Sonics loves attorney's I guess.... I prefer real heroes.

In response to EnchiladaT's comment:

As far as I know, Marvin Miller wasn't a slave owner.