In 2004, MLB established April 15 as Jackie Robinson Day because that was the day he debuted for the Dodgers and broke the league's color barrier in 1947.

The Los Angeles Dodgers are the team most closely linked to Jackie Robinson Day, because when he wore that blue No. 42 in his trailblazing MLB career, it was for the Dodgers. But a mid-career move to Hollywood for Robinson and the Dodgers doesn't wipe out where his initial color barrier-breaking actions happened: in Brooklyn.

In the world of pro sports, athletes are very attached to their numbers. Once a year, though, everyone in Major League Baseball sets theirs aside.