Cleveland Browns Hall of Famer Jim Brown set the mark that all future running backs would come to be measured against. (Photo by NFL/NFL)

Olympic Gold Medalist "Bullet" Bob Hayes introduced an element of speed to pro football and helped change the way the game is played. In this photo, Dallas Cowboys players Dick Daniels (21) and Bob Hayes (22) try to stay warm during the NFL Championship Game on December 31, 1967, at Lambeau Field in Green Bay, Wisconsin. (Photo by Vernon Biever/NFL)

One of the watershed moments of integration in pro football came in 1962 when halfback Bobby Mitchell signed with the Washington Redskins. Pictured here, Mitchell (49) of the Washington Redskins does a spin move in the open field during a 14-37 loss to the Cleveland Browns on September 15, 1963, at Cleveland Municipal Stadium in Cleveland, Ohio. (Photo by Nate Fine/NFL)

Hall of Famer Deacon Jones set a new standard for the way defensive ends played, and helped make "sack" an official stat in football. Pictured here, Jones #75 and the Los Angeles Rams played the Baltimore Colts on December 17, 1967 at Memorial Coliseum in Los Angeles, California. (Photo by NFL/NFL)

Doug Williams shattered decades of prejudice and misconceptions about the inferiority of the black quarterback in Super Bowl XXII, as he looks to pass in a 42-10 win over the Denver Broncos in Super Bowl XXII on January 31, 1988 at Jack Murphy Stadium in San Diego, California. (Photo by George Long/NFL)

Fritz Pollard was the first African-American to play in the Rose Bowl, and then became pro football's first African-American head coach. Pollard is shown here during his days at Brown University in 1916. (Photo by Pro Football Hall Of Fame/NFL)

Hall of Famer Gene Upshaw is the only man to play in three Super Bowls for the same team in three separate decades. Pictured here, Upshaw (63) fires out to block during Super Bowl XV, a 27-10 victory over the Philadelphia Eagles on January 25, 1981, at the Louisiana Superdome in New Orleans, Louisiana. (Photo by Manny Rubio/NFL)

In 1946, the league's color barrier was shattered when the Los Angeles Rams signed Kenny Washington and Woody Strode. Washington #13 is shown here breaking a tackle during a 31-14 win over the Pittsburgh Steelers on December 12, 1948, at the Los Angeles Memorial Coliseum in Los Angeles, California. (Photo by NFL/NFL)

LaDainian Tomlinson is rushing toward the Pro Football Hall of Fame and breaking every record in his path on the way there. (Photo by Donald Miralle/Getty Images)

The Minister of Defense, Reggie White, retired as the league's all-time leader in sacks before passing away in 2004 at the age of 43. (Photo by Al Messerschmidt/NFL)

Warren Moon was the first undrafted player and first African-American quarterback to be inducted into the Pro Football Hall of Fame. He is shown here during the NFL Pro Bowl on February 5, 1995, at Aloha Stadium in Honolulu, Hawaii. (Photo by NFL/NFL)

Chicago Bears running back Walter Payton (34), who was inducted into the Pro Football Hall of Fame class of 1993, dives for a touchdown during a 20-7 victory over the New Orleans Saints on October 7, 1984, at Soldier Field in Chicago, Illinois. During this game, Payton broke Jim Brown's career rushing record. (Photo by Bruce Dierdorff/NFL)

Hall of Famers Bill Willis (right) and Marion Motley were the first black men to be named all-league players as original members of the Cleveland Browns.

(Photo of Motley by Frank Rippon/NFL) (Photo of Willis by Pro Football Hall of Fame/NFL)