San Diego ? The U.S. Open brought morning fog that clung to the cliffs and spilled over to Torrey Pines Golf Course when Tiger Woods showed up for another nine-hole session Tuesday.

The setting could not have been more appropriate.

What once had been such a clear picture of this U.S. Open is now shrouded with uncertainty, starting with the left knee of the No. 1 player in the world. Woods has not played a competitive round since his runner-up finish at the Masters on April 13, having surgery two days later to clean out cartilage.

Perhaps even more startling was that Woods has not walked 18 holes since that Sunday at Augusta National – and most likely won’t until he steps to the first tee Thursday morning.

“Is it fully recovered?” he said. “Probably not.”

Woods played 171â2 holes last Wednesday in a cart, then retreated to his club in southern California for more cart golf over the weekend. Then came nine holes at Torrey on Sunday, Monday and Tuesday, and he typically doesn’t play at all the day before a major begins.

It is not the ideal way to prepare for a major, and Woods has that down to a science. What helps is that he has owned Torrey Pines as much as any other golf course in the world, winning the Buick Invitational for the sixth time in January, by a tournament-record eight shots.

That made him an overwhelming favorite for the U.S. Open – but that was before knee surgery.

“It’s difficult to take the amount of time he took off and come to a U.S. Open and dominate the way he has,” Jim Furyk said. “That being said, nothing he does surprises me.”

Sergio Garcia, among those expected to contend this week, said that didn’t make him any less of a favorite.

“It’s like Big Brown, with a crack (in the hoof),” Garcia said. “He was still the favorite.”

The last time Woods played the U.S. Open after such a long layoff was two years ago at Winged Foot, when he returned from nine weeks off to deal with his father’s death. He shots rounds of 76-76 and missed the cut for the only time in a major.

That was mental. This is physical.

In both cases, only the patient knows what’s going on. And typical of Woods, he hasn’t been forthcoming with information.

Has there been a shot that caused a twinge during practice, anything that caused him concern?

“It’s a little sore,” Woods said, “but not anything I haven’t dealt with before.”

Someone asked him to put a percentage on how his knee felt.

“It’s feeling better,” was all he said, tiring of the questions.

What surely will get his attention Thursday is having Phil Mickelson next to him on the tee, joined by Adam Scott, the first time the USGA has grouped the top three players from the world ranking.

“The guy loves a challenge,” swing coach Hank Haney said as he followed along. “And he loves this pairing with Mickelson. This will get him into the game quickly.”

That is Woods’ biggest concern – finding a rhythm that comes only from tournament golf, and finding it quickly.

The scores? They could be anything.

“It’s going to be a great test,” Woods said. “The way they have set it up with different tees, different lengths, it can play so many different ways that it’s going to be very interesting to see how the scores turn out.”