Tiger Woods withdrew from the second round of The Genesis Invitational at Riviera on Friday due to illness, bringing an abrupt end to the 15-times major champion's first PGA Tour start since last April's Masters.

Woods was one over par through six holes and had just teed off at the par-four seventh hole when he decided to call it quits and was then carted away by a rules official with his head buried in his hands.

The 48-year-old Woods, who is also serving as tournament host this week, dealt with back spasms in Thursday's first round, which he finished eight shots back of the leader and in a share of 49th place after a one-over par 72.

"He started feeling some flu-like symptoms last night. Woke up this morning, they were worse than the night previous," Woods' business partner and close friend Rob McNamara told reporters.

"He had a bit of a fever and was better during the warm-up, but then he started feeling dizzy. Doctors said he's got some type of flu and he was dehydrated. He's been treated with an IV bag and he's doing better.

"Not physical at all," McNamara added. "His back is fine. It was all medical illness, dehydration, which symptoms are reversing themselves."

The opening round included Woods' hitting a rare shank on his approach shot at the final hole, which he later blamed on back spasms.

Woods made the cut at the 2023 Masters, but withdrew before completing the third round because of plantar fasciitis and had ankle surgery later that month.

Woods returned to professional golf at the end of November in an unofficial PGA Tour event -- the Hero World Challenge -- which featured a limited field and no cut.

Two weeks later, Woods competed with his son, Charlie, at the PNC Championship, which is a 36-hole event featuring two-player teams made up of a major champion and a family member.

(Reporting by Frank Pingue in Toronto; editing by Pritha Sarkar and Leslie Adler)