Why is it Jackie Robinson Day today? Exploring significance of April 15 for MLB world

Today, every single player who suits up for an MLB franchise will have the number 42 on their back for Jackie Robinson Day.

It's a yearly tradition for MLB teams to have each and every player don that number regardless of team despite it being a retired number. Year after year, players wear these special jerseys that are not their own. Why is that?

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Why MLB players all wear 42 on Jackie Robinson day

Jackie Robinson Day is on April 15 every year

Jackie Robinson broke the color barrier in baseball long ago. In 1947, Robinson made his way from the Negro Leagues to the MLB, the first non-white player to play in Major League Baseball. He did so on Apr. 15, cementing it as one of the most important days in baseball history.

The Los Angeles Dodgers brought him, and he would go on to have a Hall-of-Fame career. He would also pave the way for tons of the sport's best players to have a place, so the league started honoring him on Apr. 15 every year beginning in 2004.

The 42 film, starring the late Chadwick Boseman as the legendary baseball player, had a quote that Pee Wee Reese, Robinson's teammate, once said to him (via NBC Sports):

"Maybe one day we will all wear 42. That way they won't be able to tell us apart.”

No one in the MLB can wear the number otherwise. New York Yankees legend Mariano Rivera had the number actively when it was retired across the league, and they allowed him to continue, but he retired in 2013. Since then, the only time anyone has had that number is on this day.

Robinson didn't have a direct path to the MLB. Things were not easy for him to break through, nor was it a simple choice for the Dodgers to make. Nevertheless, they did what they did, and the sport today is better for it.

In the grand scheme of history, there may not have been a more important player for the sport as a whole.