The Toronto Blue Jays, along with all MLB teams, are wearing the number 21 to honor Roberto Clemente Day. This is an annual MLB event celebrating Roberto Clemente, a legendary Puerto Rican Hall-of-Fame baseball player who wore the number 21 throughout his career. MLB players, managers, coaches, and umpires wear a "21" patch on their uniforms as a tribute. Additionally, players of Puerto Rican heritage, past Roberto Clemente Award recipients, and nominees for the award have the option to wear the No. 21 on their jerseys during the games on this day. The Pittsburgh Pirates, the team Clemente played for his entire career, have all players wearing No. 21 as an especially significant tribute. This tradition celebrates Clemente's extraordinary legacy both on the field and as a humanitarian.