A team's worst hitter should bat ninth, as this position in the order will come up the fewest times during the game. In the National League, this player will almost always be the pitcher.

For some reason, Tony LaRussa has done otherwise.

Second leadoff-hitter Theory: While never truly practiced, sabermetricians believe the pitcher should bat eighth and the worst batter should bat ninth. This batter will still certainly be a stronger hitter than the pitcher. So, instead of having an automatic out in front of the #1 hitter, a player more likely to get on base would bat ninth. This gives more RBI opportunities to the top of the order.