Mickey Mantle actually stepped into a drain hole that wasn't cover securely
yes. I remembered it was a groundskeeping feature. The sprinkler comment did not sound right given the era. The drain hole I think is the right story.
Always amazed me that two of the greatest ballplayers in the history of their sports, Mantle and Larry Bird, more or less played their entire career with a physical injury that suppressed some of the skill they are known for. Mantle and his speed, Bird and his shooting. Bird busted his hand playing softball after his NCAA championship game and more or less never had his fingers straight when he played in the NBA.