Tiger Woods insists he is working his "tail off" in a bid to reach the US Masters in decent form.

The 14-time major winner heads into this week's Farmers Insurance Open at Torrey Pines - a tournament at which he has been crowned champion on seven occasions - a few days after recording the worst round of his professional career.

Woods posted an 11-over-par 82 for a 13-over total at last week's Waste Management Phoenix Open.

And the 39-year-old said ahead of the California event: "I've just been working on my game, Chris (Como, his new swing coach) and I.

"The whole idea is that I'm ready for Augusta (the US Masters in April).

"I have a lot of rounds to play between now and then, and that is what we're building towards. I'm trying to peak for Augusta."

After missing the cut at the US PGA Championship in August, Woods then withdrew from contention for Ryder Cup selection as he continued to recover from back surgery.

He stressed last week that injury was not the cause of his poor effort in Phoenix, admitting the transition from previous coach Sean Foley to Como was taking some adjusting to.

And he referred to that again on Wednesday, saying of his 82 round: "I obviously have to play better.

"I'm caught right between patterns - when I have to shape shots, I'm caught right dead in between. They are so polar opposite that when I do half of one and half the other, it's pretty bad.

"I'm trying to commit to the pattern. I have been caught right between and it is about battling through that.

"Just like when I first started with Sean v Hank (Haney, his previous coach to Foley), they are completely different release patterns - I went through exactly the same phase as I am now.

"I'm always making progress, I just need to stick with it and keep doing it.

"Eventually it will start becoming more natural.

"It is a process, I'm going through it right now and Chris and I are working our tails off trying to get this. I want to get this and be ready come Augusta and the rest of the majors. But we still have some work to do."

This week's tournament will also see the return of Dustin Johnson, his first appearance on the PGA Tour in six months after he took voluntary leave of absence to tackle "personal challenges" amid allegations of a drugs ban.

Johnson has denied he has had a drug problem but admits "drinking to excess" was an issue he had to address.