And he revealed that he originally ruptured the ACL in 2007 while running at his home in Orlando after the British Open. He said he decided not to have surgery at that point, and he went on to win five of the next six events he entered (through his Target World Challenge in December).
"He's been playing way less than 100 percent for a long, long, time," his swing coach, Hank Haney, said. "It has limited him a lot in practice. He's going to come back better than he's ever been."
Woods said no date has been determined for the surgery, which will be the third in five years on Woods' left knee.
Woods said doctors have assured him the outlook is positive. Doctors have told him that the stress fractures will heal with time.
"I know much was made of my knee throughout the last week, and it was important to me that I disclose my condition publicly at an appropriate time. I wanted to be very respectful of the USGA and their incredibly hard work, and make sure the focus was on the U.S. Open," Woods said on his Web site. "Now, it is clear that the right thing to do is to listen to my doctors, follow through with this surgery, and focus my attention on rehabilitating my knee."
Woods was last seen at Torrey Pines with the U.S. Open championship trophy in hand. He played 91 holes last week, finally beating Rocco Mediate in a playoff to win his 14th major, four behind Jack Nicklaus' record of 18.
"While I am obviously disappointed to have to miss the remainder of the season, I have to do the right thing for my long-term health and look forward to returning to competitive golf when my doctors agree that my knee is sufficiently healthy," Woods wrote on his Web site. "My doctors assure me with the proper rehabilitation and training, the knee will be strong and there will be no long-term effects."
Woods had arthroscopic surgery on his left knee on April 15, two days after he finished second in the Masters in April.
Woods had committed to playing in next week's Buick Invitational. He hosts the AT&T National the week after that, at Congressional Country Club in Washington, D.C.
"I'm sorry about Tiger having to miss the rest of the year due to more knee surgery," Phil Mickelson said in a statement. "I know how frustrating it was to lose most of last summer to my wrist injury but I expect him to be back as strong as ever and look forward to competing with him as soon as possible."
"Tiger is our tour," Kenny Perry said from the Travelers Championship, where the PGA Tour is playing this week. "When you lose your star player, it definitely hurts."
Woods played only seven events worldwide this year and won five of them. He had been scheduled to play in the British Open in July and defend his PGA Championship title in August. He had never missed a major championship in his career.
"Tiger is an enormous attraction, there's no denying that," Royal & Ancient chief executive Peter Dawson said. "But the Open Championship has had many exciting finishes which Tiger has not been part of, and I'm sure there will be more. It's very sad. We're very sorry that he's succumbed to the injury and he won't be competing in the Open.
"We hope he has the speediest recovery."
"For an athlete as talented and competitive as Tiger Woods, taking the rest of the season off must have been an incredibly difficult, yet necessary decision, one that we understand and support completely," PGA Tour commissioner Tim Finchem said in a statement. "The fact that he needs additional surgery only makes his performance and victory at last week's U.S. Open all the more impressive. First and foremost, our concern -- as it would be for any of our players facing surgery or illness -- is for Tiger's health and overall well-being, both on and off the golf course. We wish him the best toward a speedy recovery."
Woods also will not be available for the Ryder Cup in September at Valhalla, just outside Louisville, Ky. According to the PGA of America, the ninth player in the U.S. standings through the PGA Championship will qualify for the U.S. team. By winning the U.S. Open, Woods mathematically clinched a spot on the team.
Woods is ultraprivate with his health and personal life, never more so than at the U.S. Open. He never mentioned the torn ACL or the stress fracture, and wouldn't say how he was treating his knee, only that it was more sore as the week went on.
Information from The Associated Press is included in this report.