LA JOLLA, Calif. — Not only has Tiger Woods not played a competitive round of golf since Masters Sunday, he hasn't even walked 18 holes since then.

Assuming he makes the 36-hole cut at the U.S. Open this week, he'll have to hoof it for at least 30,572 yards — the length of Torrey Pines (7,643 yards) times four — and that's if he hits it down the middle on every hole. Add a few expeditions into the kikuyu rough and you're talking serious mileage.

Will his surgical left knee hold up, considering the explosive force Woods generates with his 120-mph swing?

On the eve of the 108th U.S. Open, he is offering precious few clues as to the health and stability of the joint, which was scoped for a second time April 15. It's his nature to be guarded about such subjects. Some athletes don't mind talking about injuries; Woods would rather eat Phil Mickelson's divots.

During his pretournament news conference Tuesday, 18 of the 43 questions he was asked dealt with his knee or some aspect of his recovery. Those were the questions on which he was least expansive.

To wit:

"Is it fully recovered? Probably not."

"It's a little sore, but not anything that I haven't dealt with before."

"I'm good to go."

"It's feeling better."

"I'll be fine."

Rarely have a few pieces of loose cartilage been so shrouded in mystery. What we do know: a) Woods decided not to play in the Memorial a couple of weeks ago because the knee wasn't ready; b) he played a practice round last Wednesday at Torrey Pines from a motorized cart; c) he has since limited his practice rounds to nine holes.

You can read into that whatever you'd like, but none of the other players in the field of 156 is naive enough to think a bum knee means a bummed Tiger.

"I just don't see how it's going to have a negative effect on him," said Mickelson, who is paired with Woods for the first two rounds. "Players in any sport have to deal sometimes with injuries or what have you. And I just can't see a player make adjustments easier than Tiger.

"I just don't think it will be a problem."

Mickelson, a native San Diegan, has had his share of success on his home course. But Woods, who grew up in Cypress, Calif., has owned Torrey Pines since he was knee-high to a 2-iron and wore aviator glasses and braces.

He won a half-dozen age-division titles in the Junior World championships at the storied municipal course and has won the PGA Tour's Buick Invitational four consecutive years and six of the last nine. He has won $5,729,000 in the Buick alone, which is $5,000 less than Jack Nicklaus made in his career.

"I always liked playing here," Woods said. "Even though the golf course was renovated and changed, I still liked the sight lines. I didn't have a problem reading the greens, even though they changed.

"For some reason I felt very comfortable here."

The last time he played in a U.S. Open after an extended break, he missed the cut in 2006. But that was weeks after the death of his father, Earl, and his heart just wasn't in it.

"When my dad passed, coming back and playing was a lot more difficult than I thought," he said. "Usually, people go to work to get away from it. But to me it brought more feelings out when I came to work. So it was a little more difficult practicing and preparing.

"This is totally different. You can't compare the two mentally."