Woods said on his Web site Tuesday that he hurt himself hitting a shot during the third round of the Masters Tournament.
Woods described this injury as minor -- a mild sprain of his medial collateral ligament in the left knee, along with a mild strain to his left Achilles. Woods said the injury occurred when he had to squat to play a shot from under the Eisenhower tree left of the 17th fairway.
His left foot got caught in the pine straw as the momentum of the swing carried him backward. Woods hit into a front bunker and saved par on his way to 74, then shot 31 on the front nine Sunday to tie for the lead. He wound up tied for fourth, and he appeared to be limping coming to the 18th green.
This is the fourth time he has missed a tournament because of his left knee. Woods did not say when he might return, but he hopes to be back in a few weeks.
"This is precautionary. We're not at all concerned," said Mark Steinberg, his agent at IMG. "He's just listening to his doctors, which is kind of nice. He certainly didn't listen to them before the U.S. Open in 2008."
Woods won that U.S. Open in a playoff for his 14th major. He hasn't won a major since then, leaving him four behind the record 18 professional majors won by Nicklaus.
Steinberg said Woods has been in a protective boot when he's moving around and has not hit a shot since the Masters. He said Woods considered playing the Wells Fargo until Tuesday.
Woods won at Quail Hollow in 2007 and had not finished worse than 11th in four appearances until a year ago when he missed the cut with his highest 36-hole score.
The following week is The Players Championship, which Woods won in 2001, although it is not among his favorite courses. He has finished in the top 10 only four times in 13 appearances and withdrew from the final round a year ago with a neck injury.
Steinberg said there was a "reasonable chance" Woods will be at The Players Championship.
Woods, who has fallen to a No. 6 world ranking, has not won since the Australian Masters in November 2009, the longest drought of his career.