World number one Tiger Woods arrived at the WGC-Cadillac Championship with concerns over his fitness and gingerly walked off the Blue Monster Course on Sunday with new questions about his ailing back.

With the year's first major just a month away, Woods' Masters preparations may have to be quickly reworked as he deals with back spasms that have plagued him through his last two events.

After pulling out of the final round of the Honda Classic a week earlier, the defending champion looked ready to make another unscheduled early exit at Doralon Sunday when his back problems flared up again on the sixth following an awkward shot out of the bunker.

"It is back spasms, so we've done all the protocols and it's just a matter of keeping everything aligned so I don't go into that," said Woods. "It's basically started on six, the second shot out of the bunker, my foot was out of the bunker.

"That's what set it off and then it was done after that, just see if I could actually manage through the round, keep the spasms at bay."

Woods, a seven-time winner of the WGC-Cadillac, had surged into contention on Saturday with a third round 66 to start the final day three shots behind but returned a six-over 78 to finish tied for 25th.

The 14-times major winner did not make a birdie in his final round and walked gingerly off the course having completed his first PGA Tour event of the season.

"If I feel good, I can actually make a pretty decent swing," said Woods. "You saw it yesterday.

"I actually can make some good swings and shoot a good score but if I'm feeling like this, it's a little tough.

"I mean, it was just one thing that set it off and as I say, I had a quick turnaround from last week.

"Normally things like this, you shut it down for a while and then get back up and get the strength and everything developed around it."

Woods will take next week off as scheduled and continue to undergo treatment on his back but plans to be ready for Bay Hill the following week and the defense of his Arnold Palmer Invitational title.

"I don't know, just let me get through this day, get some treatment and we'll assess it as time goes on," said Woods, when asked if he would rethink his schedule.

"It will be nice to take this week off and get everything ready for Bay Hill.

Woods has battled numerous injuries throughout his career but says the back is a far more debilitating problem.

For Woods, the only good thing to come out of the WGC-Cadillac was a welcome end to testing week.

"It's over," said Woods.

"It's finally done, which is good."