Bryson DeChambeau raised eyebrows when he was spotted using a protractor to mark pin positions in his green book last month, and it has led to the PGA Tour banning the act.
The American, known as the Scientist for his approach to the game, was initially told the practice was legal and did not go against the rules - but that decision has been reversed.
“The USGA has ruled that the use of a protractor (also known as a drawing compass) during a stipulated round is a violation of Rule 14-3a of the Rules of Golf,” a statement sent to players read. “It is considered ‘unusual equipment that might assist him in making a stroke or in his play.’”
DeChambeau, who refused to comment on the decision, said: “I’m figuring out the true pin locations,” DeChambeau said. “The pin locations are just a little bit off every once in a while, and so I’m making sure they’re in the exact right spot. And that’s it.”