Major League Baseball has honored Robinson many times since his death. In 1987, both the National and American League Rookie of the Year Awards were renamed the "Jackie Robinson Award" in honor of the first recipient (Robinson's Major League Rookie of the Year Award in 1947 encompassed both leagues). On April 15, 1997, Robinson's jersey number, 42, was retired throughout Major League Baseball, the first time any jersey number had been retired throughout one of the four major American sports leagues. Under the terms of the retirement, a grandfather clause allowed the handful of players who wore number 42 to continue doing so in tribute to Robinson, until such time as they subsequently changed teams or jersey numbers. This affected players such as the Mets' Butch Huskey and Boston's Mo Vaughn. The Yankees' Mariano Rivera, who retired at the end of the 2013 season, was the last player in Major League Baseball to wear jersey number 42 on a regular basis. Since 1997, only Wayne Gretzky's number 99, retired by the NHL in 2000, has been retired league-wide. There have also been calls for MLB to retire number 21 league-wide in honor of Roberto Clemente, a sentiment opposed by the Robinson family.