Mexico's Abraham Ancer was issued a two-stroke penalty after Thursday's opening round of the 85th Masters for unknowingly touching sand in a 15th-hole bunker before making a shot.
The punishment means the 31st-ranked player in the world will be credited with an opening-round three-over par 75 instead of a 73 at Augusta National.
Ancer, who shared 13th last year in his Masters debut, had signed his scorecard and departed the scoring area when video evidence was obtained and reviewed by the tournament committee.
After review for a violation of the rule penalizing the touching of sand in a bunker directly behind the ball, officials ruled that Ancer committed a violation before his third shot at 15.
The touching of the sand was deemed visible to the naked eye. Had that not been the situation, no penalty would have been applied.
Instead, Ancer's score on the hole rose from a bogey-6 to a triple-bogey 8, boosting his total score by two as well.