Interleague play

Interleague play in Major League Baseball refers to regular-season baseball games played between an American League (AL) team and a National League (NL) team. Interleague play was first introduced during the 1997 Major League Baseball season. Prior to that, matchups between AL teams and NL teams occurred only during spring training, the All-Star Game, other exhibition games (such as the now defunct Hall of Fame Game in Cooperstown, New York), and the World Series. Unlike modern interleague play, none of these contests, except for the World Series, counted toward official team or league records.

From 1997 to 2001, regular season interleague play occurred only on a geographical basis, with divisions in each league (the West, Central, and East) assigned to play their counterpart in the opposite league. In 2002, MLB introduced a system of rotating matchups, allowing interleague, cross-country games to occur in the regular season for the first time. In 2023, MLB began scheduling all 30 teams to play each other every year.