Koepka has been nursing the injury since last month.
CNN  — 

Team USA will be without the world’s number one ranked golfer at the Presidents Cup due to a knee injury.

Brooks Koepka announced he wasn’t able to play in the Cup’s 13th edition, which will be held at the Royal Melbourne Golf Club in Melbourne, Victoria, in December.

“Today, I am announcing my withdrawal from the USA Presidents Cup team because of my knee injury… despite constant medical care and rehab, I am not able to play golf at this time,” Koepka said in a statement. “I consider it to be a high honor to be part of the 2019 team and I regret not being able to compete.”

Koepka has been struggling with the injury since last month when he reaggravated his knee at the CJ Cup in South Korea, and had to withdraw.

He said he told captain Tiger Woods that he would make every effort to make it to Melbourne to play, but he needs more time to heal.

“I’m sorry I won’t be able to represent the Red, White, and Blue this time around and I wish my teammates nothing but the best as they work to retain the Presidents Cup for the USA.”

Woods chose Rickie Fowler to replace Koepka on the team.