Collin Morikawa assessed two-stroke penalty for use of green-reading materials

Collin Morikawa was assessed a two-stroke penalty stemming from an infraction on the fourth hole of his third round at the Hero World Challenge, PGA TOUR Communications announced Sunday afternoon.

Morikawa violated Model Local Rule G-11, which restricts players from using green-reading materials other than their yardage book that has been approved for use in the competition.

According to PGA TOUR Chief Referee Stephen Cox, Morikawa’s caddie Jonathan Jakovac used a level on the practice putting green to calculate the slope of the surface. That formula was then written into Morikawa’s yardage book and used on the fourth green, which triggered the violation.

“It comes down to use of this handwritten note,” Cox said. “Because he used it for assessing the putt during his third round then he was assessed a two-stroke penalty. Fortunately, that is the only time the player or caddie has accessed that information … and on that basis, the breach remained at two strokes.”

Cox was informed of the potential violation on Saturday evening by Matt Fitzpatrick, Morikawa’s third-round playing partner.

Cox then met with Jakovac on Sunday morning, who confirmed the use of the formula was isolated just to the fourth hole of the third round. Morikawa was informed of the violation “10-15 minutes” before his tee time, per Cox.

“This is a very complicated issue,” Cox continued. “We respect the traditional methods of people wanting to have notes in their yardage book. That is something that’s been going on for many years. And obviously, when we drafted this Model Local Rule we wanted to protect that. Some players and caddie take more notes than others. We were very specific in that these handwritten notes needed to be obtained through traditional methods to protect the fundamental skill of reading greens within our sport … If he had gone there using traditional methods and estimated with his feet or other means the percentages of slope on that practice putting green, 1%, 1.5% or 2% to gauge the amount of break on a particular length of putt, that chart or formula that the caddie has devised would be fine.”

Cox added that Morikawa is allowed to use the level to calculate the slope of the practice green and commit the formula to memory. However, a violation occurred because the formula was written into his yardage book and subsequently used.

“We’ve been very specific for those players that do use formulas, it’s fine, you do need to retain that as your memory for then to take onto the course,” Cox said.

“[Morikawa] was very frustrated,” Cox added. “This is a very complicated rule.”

Model Local Rule G-11 was implemented in 2022. Cox said it had been violated in PGA TOUR play before, though not specifically in this manner.

Morikawa’s third-round score was adjusted from 68 to 70. It moved him from 10 under to 8 under, eight shots behind 54-hole leader Scottie Scheffler.

"At the end of the day we made the mistake and it's on us," Morikawa said after his final round. "Thankfully it only happened that one time."