Moses Fleetwood Walker
The first African-American major leaguer was not Jackie Robinson but was Moses Walker.
He was a catcher, back in the days where they used no equipment, not even gloves.
Playing for the Toronto Blue Stockings of the American Association, his MLB debut was May 1, 1884 against the Louisville Eclipse. (Don't you love the names of those old teams?)
Walker's teammate and star pitcher, Tony Mullane, stated Walker "was the best catcher I ever worked with, but I disliked a Negro and whenever I had to pitch to him I used to pitch anything I wanted without looking at his signals."
Unfortunately he suffered a season-ending injury in July and never made it back to the majors. He played 42 games and batted .261.
Shortly thereafter baseball entered into its "Gentleman's Agreement" to exclude blacks, which lasted until 1947.
I'm sure Jackie Robinson was a brave and swell guy, but he was a Dogger, so fuck him.