Tiger Woods has withdrawn from The Genesis Invitational at Riviera Country Club in Pacific Palisades, California, due to illness, the PGA Tour announced on Friday. PGA Tour rules official Mark Dusbabek said Woods' illness is not related to his ankle or back.

Rob McNamara of TGR Ventures said Woods began experiencing "flu-like symptoms" Thursday night.

On Saturday, Woods confirmed his illness with a post on X.

"I would like to confirm that I had to withdraw from @thegenesisinv due to illness, which we now know is influenza. I am resting and feeling better. Good luck to the players this weekend. I’m disappointed to not be there and want to thank @GenesisUSA and all the fans for the support."

The Genesis Invitational marked Woods' first PGA Tour tournament since he withdrew from the 2023 Masters, but it has ended the same.

The 15-time major champion shot 1-over par during the first round, admitting that his "back was spasming" and "locking up" during the final holes on Thursday. He added, “It was one of those days, just never really got anything consistently going and hopefully tomorrow I can clean it up."

ROUND 1: Woods finishes one over par Thursday at Genesis Invitational

Woods, 48, got off to a better start on Friday, starting the second round with a birdie on the first hole, before surrendering back-to-back bogeys on holes four and five. He was 1-over par through six holes before ending his day early. Woods was carted back to the clubhouse by a rules official after withdrawing from the tournament.

McNamara echoed Dusbabek in saying that Woods' withdrawal was not due to physical issues.

"His back is fine. It was all medical illness, dehydration, which is now, the symptoms are reversing themselves now that he’s had an IV," McNamara said.

Woods serves as the tournament host at The Genesis Invitational. Ahead of the tournament on Tuesday, he shared his intention to win The Genesis Invitational for the first time in his career: "I would not have put myself out here if I didn't think I could beat these guys and win the event. That's my mentality."

But his health prevented Woods from reaching that goal.

Woods last played in a PGA Tour event at the 2023 Masters, where he said he was in "constant" pain. The pain became too much to bear and Woods withdrew from Augusta National before third-round play resumed on Sunday due to injury. He had ankle surgery soon after and didn't play in any other major tournament last year.

Woods competed in the Hero World Challenge in December and finished in 18th place. He also played in the PNC Championship in December 2023 alongside his son, Charlie, and finished tied for fifth.

The 2024 Masters takes place April 11-14.

Contributing: The Associated Press

This article originally appeared on USA TODAY: Tiger Woods withdraws from Genesis Invitational due to illness