<P> In spring training games, the home team chooses whether the designated hitter is used . Occasionally National League teams opt to use the designated hitter, usually when a player is recovering from an injury . </P> <P> The rationale for the designated hitter rule arose comparatively early in the history of professional baseball . It was observed that, with a few exceptions--most notably Babe Ruth, who began his career as a pitcher with the Boston Red Sox--pitchers are usually selected for the quality of their pitching, not their hitting, and that most pitchers were weak hitters who had to be batted ninth in the batting order and pinch - hit for late in games when their team was trailing . The designated hitter idea was raised by Philadelphia Athletics manager Connie Mack in 1906, though he was not the first to propose it . The rumors were that he grew weary of watching Eddie Plank and Charles Bender flail at pitches when at bat . Mack's proposal received little support and was even lambasted by the press as "wrong theoretically". The notion did not die . In the late 1920s, National League president John Heydler made a number of attempts to introduce a 10th - man designated hitter as a way to speed up the game, and almost convinced National League clubs to agree to try it during spring training in 1929 . </P> <P> However, momentum to implement the DH did not pick up until the pitching dominance of the late 1960s . In 1968, Denny McLain won 31 games and Bob Gibson had a 1.12 ERA, while Carl Yastrzemski led the American League in hitting with only a . 301 average . After the season, the rules were changed to lower the mound from 15 to 10 inches and change the upper limit of the strike zone from the top of a batter's shoulders to his armpits . In addition, in 1969 spring training, both the American League and National League agreed to try the designated pinch hitter (DPH), but they did not agree on the implementation . Most NL teams chose not to participate . On March 6, 1969, two games utilized the new DPH rule for the very first time . Two newly formed expansion teams, the Montreal Expos and the Kansas City Royals, would participate in one such game, and the New York Yankees and Washington Senators in the other . On March 26, 1969, Major League Baseball nixed the idea for the time being . However, a four - year trial in which the International League and four other minor leagues started using the DH for their games began that year . </P> <P> Like other experimental baseball rule changes of the 1960s and 70s, the DH was embraced by Oakland A's owner Charlie O. Finley . On January 11, 1973, Finley and the other American League owners voted 8--4 to approve the designated hitter for a three - year trial run . On April 6, 1973, Ron Blomberg of the New York Yankees became the first designated hitter in Major League Baseball history, facing Boston Red Sox right - handed pitcher Luis Tiant in his first plate appearance . "Boomer" Blomberg was walked . The result of the first season of the DH was that the American League posted a higher batting average than the National League, something which has remained consistent to this day . </P>

How come the nl doesn't have a dh
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