As much as Tiger Woods wanted to be healthy and ready to compete in the U.S. Open next week, he became increasingly concerned with how much additional time he would miss if he aggravated injuries to his left knee and his left Achilles tendon in the national championship.

So he pulled out of the Open on Tuesday. As his Twitter post expressed it: "Short-term frustration for long-term gain."

But Woods did not provide a definition for short-term, which leaves his fans wondering if he will be able to play in the AT&T National at Aronimink Golf Club, which begins June 30, just over three weeks away.

"I hope to be ready for AT&T National, the next two majors, and the rest of the year," he said on his website.

Certainly the fact that Woods won't be risking further injury next week gives him a better chance of teeing it up in Newtown Square for an event that benefits the Tiger Woods Foundation.

Right now, though, it's about the U.S. Open at Congressional Country Club, a course where Woods won the AT&T National two years ago, and when exactly Woods will be able to continue his pursuit of Jack Nicklaus' record of 18 career major championships.

Woods hasn't played since May 12 when he pulled out of The Players Championship after nine holes of his opening round. During the May 24 media day for the AT&T National, Woods said he felt wearing a boot and using crutches would give his knee and Achilles "ample rest and ample healing time" for the Open.

But the injuries did not come around as he would have hoped, and he will miss the Open for first time since 1994, when he had just graduated high school.

"I am extremely disappointed that I won't be playing in the U.S. Open," he said on his website, "but it's time for me to listen to my doctors and focus on the future. I was hopeful that I could play but if I did, I risk further damage to my left leg. My knee and Achilles tendon are not fully healed."

Woods contacted Mike Davis, executive director of the United States Golf Association, on Tuesday morning with the news.

It's the latest setback for Woods as he tries to find the game that seemed to still be with him when he won the 2009 Australian Masters, which is his last victory.

Woods fell from No. 1 in the World Golf Rankings on May 23, the first time he's been out of the top spot since Masters week of 1997 when he won his first of 14 majors, and he is No. 15 in the most recent rankings.

Woods hurt the knee and Achilles attempting a shot off pine straw in the third round of the Masters. He did not play again until The Players and said later that he came back too soon.

With Woods sitting out the U.S. Open, it will mark 12 straight majors he has not won, the longest drought of his career. He hopes to be back next month in the British Open at Royal St. George to resume his pursuit of Nicklaus' record of 18 majors.

Mark O'Meara said he thought Woods' withdrawal was a good thing for his friend.

"You're throwing yourself back in the fray at a major when you haven't really played besides Augusta - you can't count The Players," he told the Associated Press. "To be prepared to do that, you've got to have some reps, and not reps at home.

"He drives the needle and he always will. I'd rather see him come back when he's ready. And if he's not prepared . . . he shouldn't come back."

Contact staff writer Joe Juliano at 215-854-4494 or jjuliano@phillynews.com. Read his blog, "Golf Inq," at www.philly.com/golfinq.

This article contains information from the Associated Press.