Los Angeles - The two-stroke penalty assessed to American Denny McCarthy in the second round of the Phoenix Open has been rescinded as golf's governing bodies acknowledged confusion over the new rule that led to it.

McCarthy was penalized after his caddie, Derek Smith, stood behind him before he played a shot into the 15th green at TPC Scottsdale on Friday.

Rule 10.2b(4), which came into effect on January 1, prohibits a player from having his or her caddie deliberately stand behind him or her when the player begins taking a stance.

The rule is designed to prevent a player from relying on a caddie's advice in aiming at the intended target, but it acknowledges that there "is no set procedure" for determining when a player has begun to take a stance".

"It is clear that there is a great deal of confusion among players and caddies on the practical application of the new rule during competition, as well as questions surrounding the language of the rule itself and how it should be interpreted," the PGA Tour said in a statement on Saturday announcing the penalty had been withdrawn.

The move changed McCarthy's second-round score from a 67 to 65.

The tour said it had consulted with the US Golf Association and the Royal & Ancient Golf Club, golf's global governing bodies, about how to interpret the rule.

"We will be working vigorously with the USGA and The R&A over the coming days to further analyze and improve the situation with this rule," the tour said. "The USGA and The R&A will be making an announcement shortly."

China's Li Haotong was controversially penalized two shots on the final hole of the Dubai Desert Classic last week because his caddie was standing directly behind him when he made his putt.

European Tour commissioner Keith Pelley branded that ruling "grossly unfair".