INTERLEAGUEPLAY
Interleague play
Interleague play is the practice of regular season Major League Baseball games played between teams in different leagues. Before being introduced in the 1997 season, matchups between teams in the American League and National League only occurred during spring training, the All-Star Game, other exhibition games, and the World Series. Unlike modern interleague play, none of these contests, except for the World Series, counted toward official team or league records.The above text is a snippet from Wikipedia: Interleague play
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