Tiger Woods is set to be out of action for between four to six weeks following arthroscopic surgery on his left knee.
The world number one, who was second in the Masters at the weekend, will now be unable to defend his Wachovia Championship title from 1-4 May.
Woods has had two previous operations on the same knee.
"I made the decision to deal with the pain and schedule the surgery for after the Masters," said Woods, 32, on his official website.
"The upside is that I have been through this process before and know how to handle it.
"I look forward to working through the rehabilitation process and getting back to action as quickly as I can."
The American, who could also miss the Players Championship in May, had hoped to achieve a Grand Slam of majors this season but his bid came to an end at the first hurdle in the Masters, which was won by Trevor Immelman.
Woods first had an operation on the knee in 1994 to remove a benign tumour and then had arthroscopic surgery in December 2002.
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"Tiger has been experiencing pain in his knee since the middle of last year," said his manager Mark Steinberg.
"When he had it looked at by his doctors, arthroscopic surgery was recommended. Tiger has played through the pain in the past but knew it would be better for him to have the procedure done as early as possible."
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