Dead-ball era

In major league baseball, the dead-ball era refers to a period from about 1900 to 1920 in which run scoring was low and home runs were rare in comparison to the years that followed. In 1908, the major league batting average dropped to .239, and teams averaged just 3.4 runs per game, the lowest ever. Spacious ballparks limited hitting for power, and the ball itself was "dead" both by design and from overuse. Ball scuffing and adulteration by pitchers, particularly the spitball, were allowed, putting hitters at a disadvantage.

The era ended very suddenly; by 1921, offenses were scoring 40% more runs and hitting four times as many home runs as they had in 1918. There is no consensus among baseball historians as to what caused the change.