You can read about it in this Deadspin article by DeArbea Walker. As the first African-American to play in the modern major leagues Robinson was a notable person and his career playing at that level made him a member of the baseball hall of fame.
Sadly, the writer leaves out some important facts in her story while pushing some unrelated nonsense.
Originally from Georgia, Jackie Robinson attended high school in Pasadena, CA and developed into a spectacular all-around athlete, a four sport letter winner at UCLA and the NCAA champion in the long jump. He spent time coaching and was a player for the Kansas City Monarchs in the Negro leagues.
It wasn't possible for Robinson or any other ballplayer, black, white or purple, to simply walk into a baseball clubhouse and become a team member. Then, as now, the club's management had to sign him to a contract and assign him to either the big league club or one of its minor league affiliates. Brooklyn Dodgers president and general manager Branch Rickey believed that it was highly likely that baseball would soon become integrated and wished to sign the prospect that he felt had the best chance to succeed at that level. Robinson was his choice and was assigned to the AAA Montreal Royals. The next season he began his tenure as a star for the Brooklyn Dodgers. If not for Branch Rickey, Robinson may well have languished in the negro leagues like so many others. The Deadspin essay doesn't even mention Branch Rickey, who was the real hero in this affair.
Also forgotten, as usual, were native Americans in Major League Baseball. Nobody can be sure but it's generally agreed that the first native American big leaguer was Louis Sockalexis, a Penobscot from Maine who patrolled the outfield for the Cleveland Spiders from 1897-1899.
He was followed by one of the all-time diamond greats, Charles Albert "Chief" Bender. The Chief had a 24 year career with four different ball clubs beginning in 1903 and a mound record of 212-127 with a lifetime ERA of 2.46 and 1,711 strikeouts. He pitched three complete games for the Philadelphia Athletics in the 1905 World Series victory over the New York Giants. He was admitted to the Hall of Fame in 1953.
Perhaps one of the most famous ballplayers of the twentieth century and one of the country's greatest all-around athletes was born in what is now Oklahoma in 1887. Jim Thorpe, a Sac and Fox, is remembered most for his exploits in the 1912 Olympic Games in Stockholm, Sweden and his spectacular college and professional football career. Less well known is his time spent in Major League Baseball in the years 1913-1919.
Other native Americans have since spent time in The Show but they, and the African-American players that began playing in 1947 had an advantage that these three did not. Sockalexis, Bender and Thorpe, despite being born in the US, were not US citizens. Native Americans, with some exceptions, were not granted citizenship until passage of the The Indian Citizen Act in 1924.
Chief Bender Lakepowelllife.com