MLB players wear number 21 primarily to honor Hall of Famer Roberto Clemente and his legacy on and off the field.

Quick Scoop: Why number 21?

  • Number 21 is most closely associated with Roberto Clemente, the Pittsburgh Pirates star outfielder and humanitarian.
  • MLB has an annual Roberto Clemente Day (now fixed on September 15), when players, coaches, and staff can wear 21 or a 21 patch to celebrate his life and community work.
  • Puerto Rican players, Roberto Clemente Award nominees, past award winners, and now any player who requests it (with team approval) can wear 21 on Clemente Day as a tribute.
  • Teams like the Pirates, and sometimes others such as the Blue Jays in specific tribute games, wear 21 to highlight Clemente’s impact and charitable legacy, not just his statistics.

A tiny bit of story

Think of it as baseball’s way of saying: this number stands for more than talent.
When you see 21 across MLB on Roberto Clemente Day, it’s a visible reminder of a player who combined elite performance with humanitarian work and died while bringing aid to earthquake victims. The number has become a symbol of respect, service, and Latino and Puerto Rican pride in the sport. TL;DR:
They’re wearing 21 as a tribute to Roberto Clemente—his number, his humanitarian legacy, and his importance to MLB culture and Puerto Rican/Latino baseball history. Information gathered from public forums or data available on the internet and portrayed here.