The Toronto Blue Jays players are wearing number 21 to honor Roberto Clemente on Roberto Clemente Day, which is observed annually in Major League Baseball on September 15. MLB players, managers, coaches, and personnel wear the number 21 or patches with number 21 to commemorate Clemente's legacy as a Hall of Famer, humanitarian, and Puerto Rican baseball icon. On this day, some Puerto Rican players, previous Roberto Clemente Award winners, and nominees, including members of the Blue Jays, wear the number 21 jersey as a tribute to Clemente, who was known not only for his remarkable baseball career but also for his extraordinary character and community contributions. This tradition started with MLB formally recognizing the day and expanding the honor over the years to include more personnel wearing number 21 or patches in Clemente's memory.