The rays (and many other MLB players) are wearing the number 21 to honor Roberto Clemente Day. This day commemorates the life and legacy of Roberto Clemente, a Baseball Hall of Famer, Puerto Rican humanitarian, and trailblazer for Latino players. MLB allows award nominees, past award winners, players of Puerto Rican descent, and some others to wear the number 21 during games on this day. The Tampa Bay Rays requested special permission to have many of their Latino players and coaches wear the number 21, making a special tribute to Clemente’s impact on baseball and humanitarian causes. This tribute is marked by the number 21 on jerseys and patches worn league-wide around September 15 each year.