Here are the voting procedures used to select rosters for all-star games by the major sports leagues.
Major League Baseball
Starters: Eight position players chosen by fan balloting.Reserves: The first eight reserves, five starting pitchers and three relievers are chosen by the players, coaches and managers' balloting. The manager then picks five more pitchers and three position players with input from the commissioner's office. In doing so, he must be certain that each team has at least one representative. The 33rd and final roster spot is filled by an online vote.