On this date in 1930, the rules committee of MLB decided that a ball that bounces into the stands will no longer be a home run.
The committee determines that a ball that bounces into the stands will be called a ground-rule double. A true ground-rule double is granted only when the ground rules of a specific ballpark come into play. Each ballpark has its own set of ground-rules. When, for example, a ball is hit into the ivy of Wrigley Field, the hit is ruled a ground-rule double. Another example from Wrigley Field is the basket that is attached to the outfield wall to keep fans from getting on the field. If a fly ball ends up in the basket, it is ruled a home run.
It is estimated that hitters that played in the era before the rule change, hit about two bouncing home runs per year so Babe Ruth’s number of home runs would have been reduced by twenty-two if the rule had been in place from his debut with the Boston Red Sox.