On December 10, 1972, the American League passes a new rule allowing the use of a “designated hitter.” Although the AL says it will employ the designated hitter on a three-year trial basis, the DH will eventually become a permanent part of the league’s rules.

The concept that permits a team to designate a player to bat in place of the pitcher will be implemented in some measure by most collegiate and professional circuits, with the National League and Japan’s Nippon Professional Baseball’s Central League being the notable exceptions.

This concept was initially discussed in 1891 and 1928.