why is mlb wearing 21

Major League Baseball players and personnel wear the number 21 to honor Roberto Clemente on Roberto Clemente Day, which is observed around September 15 each year. Clemente, a Hall of Famer and humanitarian, wore No. 21 throughout his career with the Pittsburgh Pirates. MLB celebrates his legacy by having all players, managers, coaches, and umpires wear a "21" patch, and players of Puerto Rican heritage as well as Clemente Award nominees have the option to wear No. 21 on their jerseys. This tribute recognizes his outstanding baseball achievements and his humanitarian efforts before his tragic death in 1972 while delivering earthquake relief supplies.