Tiger Woods was dealing with a back injury as he finished 1-over par at Thursday's opening round of the Genesis Invitational.

Woods has never before won the tournament at the Riviera Country Club, which he has entered 12 times.

Woods told reporters after the first round that his back locked up on the 18th hole, which he said he "shanked."

"My back spasmed on it," Woods said. "It had been spasming over the last three holes and it just locked up on me and didn't move, didn't rotate."

Woods said he had previously suffered back spasms at home but had not recently experienced them during competition, according to ESPN's Mark Schlabach.

The 15-time majors winner has undergone back surgery multiple times.

Most recently Woods underwent a microdiscectomy to remove a disc fragment causing nerve pain in 2021.

Back issues aren't the only injuries Woods has been dealing with. His appearance at the Genesis Invitational marked his return to the PGA Tour for the first time since undergoing surgery on his right foot last April.

After visibly limping through the beginning of the 2023 Masters, Woods withdrew early from the tournament due to a foot issue stemming from 2021 car crash which injured his right leg.

After initially attempting to avoid surgery, Woods underwent a procedure fusing two of the bones in his right foot together nine months ago.

Woods told reporters after the tournament that his right foot was not a problem on Day 1, but that he was experiencing soreness in his right leg in addition to the back spasms.

"Things are a little bit sore, but that's to be expected," Woods said. "It's nothing that we weren't prepared for, and we've got some work to do tonight and tomorrow."

The Genesis Invitational has a 36-hole cut this year, so Woods will need a more consistent Friday in order to stay in the competition. He ended the first day of the invitational having hit seven pars, five birdies and six bogeys as he tied for 57th among 70 competitors.

Patrick Cantlay, who is seeking his ninth career PGA Tour victory, took an early lead with a 7-under-par 64.

Woods will look to close the distance between himself and the top of the leaderboard when he tees off Friday at 2:54 p.m. ET.