What significant change in the basic rules of major league baseball first occurred in the 1973 season, and is still used today?

In 1973, the American League introduced a radical rule change aimed at boosting offensive production. This new rule allowed a player to bat in the place of the pitcher without the pitcher having to be removed from the game. The change was a direct response to a period in the late 1960s known for dominant pitching and low scoring, and league officials hoped that replacing a weak-hitting pitcher in the lineup with a professional batter would generate more action and excitement for fans.

The first player to officially appear in a game as a designated hitter, or DH, was Ron Blomberg of the New York Yankees. While the American League embraced the new position, the more traditional National League famously resisted it. For nearly five decades, this created a major strategic difference between the two leagues, a source of constant debate among baseball purists. This finally changed in 2022, when the National League permanently adopted the DH, making the rule a universal standard across all of Major League Baseball.