Tiger Woods has been forced to pull out of the Farmers Insurance Open after suffering a recurrence of his back problem in the opening round at Torrey Pines.

The former world number one, who was playing just his second event of the year after last week's disappointing performance in Phoenix, appeared to be struggling from his first tee shot, and he was only able to last 11 holes.

Woods played erratically throughout his time on the course, and when a double-bogey left him two-over-par, he shook hands with partners Rickie Fowler and Billy Horschel before departing.

"When we had that break, my back just never loosened back up again, and when we went back out, it just got progressively tighter," Woods told reporters.

"It's frustrating that it started shutting down like that. I was ready to go. I had a good warm-up session the first time around. Then we stood out here and I got cold and everything started deactivating again, and it's frustrating that I just can't stay activated.

"It's just my glutes are shutting off. Then they don't activate and then, hence, it goes into my lower back. So I tried to activate my glutes as best I could, in between, but they never stayed activated."

A two-and-a-half-hour delay prevented Woods from teeing off on time at Torrey Pines.