Golfers will have to navigate a number of challenges during the 2025 U.S. Open this week, but there is one in particular that they may not be accustomed to. Ryan Herrington of Golf Digest wrote on Tuesday about a local rule at Oakmont Country Club in Oakmont, Pennsylvania, that will require some extra thought from players in the U.S. Open field. The rule pertains to the practice green, which is actually connected to the ninth green. The ninth green at Oakmont is so massive that the portion of the 22,000-square-foot surface closest to the clubhouse is used as the practice green. There are blue stakes and a sign near the middle of the green that indicate where the actual ninth green and practice area are separated. Golfers who are playing the ninth hole and hit their approach shot long and into the practice area will likely be entitled to free relief. As Herrington explained, USGA rule 16.1d states that a player can take relief when their ball ends up in a spot where a practice hole interferes. That is the friendly part. What golfers need to be even more cognizant of is USGA rule 5.2b, which prohibits players from practicing "on the course" prior to a round. If a player were to make a stroke on an actual area of the course prior to playing their round, that player would be assessed a one-stroke penalty on the first hole. A second violation would result in the player being disqualified from the tournament. That means players who are practicing their putting at Oakmont need to be certain they do not cross the blue stakes into the area of the ninth green that is part of actual play. Herrington notes that the USGA sent a memo to golfers ahead of the U.S. Open reminding them of the unique practice green setup. Even still, the extremely unique rule is one that will have to remain on the minds of golfers and their caddies.