Can an umpire use a mark on the batter to determine whether a pitch hit the knob of the bat instead of the batter?

An umpire can indeed use a mark on the batter to determine whether a pitch hit the knob of the bat instead of the batter. This practice is acceptable because umpires are tasked with making accurate and fair judgments based on all available evidence during a game. If there is a visible mark on the batter's body that can indicate contact with the bat rather than the batter themselves, it provides helpful context for the umpire to make an informed decision.

The ability to reference marks left from a pitch can aid in assessing whether the pitch resulted in a hit-by-pitch situation or if it simply made contact with the bat. This type of evidence allows for better accuracy in officiating, contributing to the overall integrity of the game. By considering marks on the player, the umpire is using all tools at their disposal to uphold fairness in the competition and ensure that the rules are applied correctly.