In little more than a month, Tiger Woods went from being tough to beat to having a tough time even playing. Woods said Wednesday that soreness in his left elbow would keep him from defending his title next week in the AT&T National at Congressional, and that he would not compete again until the British Open next month at Muirfield. This is the sixth straight year that injury has kept him from either playing a tournament or finishing one. The culprit this time is a strain in his left elbow. The problem first became apparent during the opening round of the U.S. Open last week at Merion, when he was flexing his left wrist or dangling his arm behind his back after shots out of the thick, punishing rough. “I was examined after I returned home from the U.S. Open, and the doctors determined I have a left elbow strain,” Woods said on his website. “I have been advised to take a few weeks off, rest and undergo treatment. I’ll be ready to go for the British Open, and I’m looking forward to playing at Muirfield.” His injury is a blow to the AT&T National, which benefits the Tiger Woods Foundation. This will be the third time since it began in 2007 that Woods has missed the tournament because of injury — knee surgery in 2008, his left Achilles tendon in 2011 and an elbow injury this year. “Any time you have Tiger in the field, it certainly adds to it a lot,” tournament director Greg McLaughlin said. “But we have a very nice field this year and we look forward to a great AT&T National.” Masters champion Adam Scott and U.S. Open champion Justin Rose are among those scheduled to play. McLaughlin said Woods is to be at Congressional at least on Wednesday to take part in the opening ceremonies. Woods was not specific about when or how the latest injury happened. He first showed signs of being hurt after hitting shots in the rough during the rain-delayed opening round at Merion, though he told a USGA official it was “fine” when he left the course Thursday evening. After finishing the first round Friday morning, he said only that the reason he grimaced after shots out of the rough was because of “pain” and that he felt it on a few shots. That afternoon, he revealed that he first hurt his elbow at The Players Championship, but he declined to say which round or on what kind of shot. Woods won The Players Championship on May 12 for the first time in 12 years. It was his fourth PGA Tour win of the season. Woods picked up those four in just eight starts worldwide, and the win at Sawgrass was his third victory in his last four tournaments. The exception was the Masters, where he tied for fourth, four shots out of a playoff. But the last two tournaments have produced a surprising outcome. At the Memorial, where Woods was a five-time winner and the defending champion, he had the worst nine-hole score of his career with a 44 on the back nine that led to a 79 in the third round. He tied for 65th and finished 20 shots behind, his largest deficit for a full-field event. At Merion, he wound up with a 13-over 293, his highest score ever for the U.S. Open and tied for his highest 72-hole score in any major. Even so, the announcement Wednesday was surprising. Woods had said Friday at Merion that he would not have withdrawn even if it were not the U.S. Open. He was not asked about his elbow the rest of the week. It will be the 10th time Woods is unable to defend a title in official PGA Tour events, with six of those related to reconstructive surgery on his left knee after he won the 2008 U.S. Open at Torrey Pines. The last time he failed to defend was in 2010 at Bay Hill, when he was returning from the scandal in his personal life. His website said he felt minor discomfort before going to Merion and aggravated the area last week. Woods extended his regrets to AT&T, secondary sponsors and fans in Washington for not being able to play. “The AT&T National means a lot to me and my foundation,” he said. “It’s especially difficult not defending at my own tournament. It’s going to be a great event, and I look forward to being there to provide my support.” AT&T is under contract as title sponsor through 2014. The Dallas-based company recently announced that it would take over as title sponsor for the Byron Nelson Championship starting in 2015. It also is the longtime title sponsor at Pebble Beach. The British Open is July 18-21 at Muirfield, where Woods’ bid for the calendar Grand Slam ended in 2002 when he was caught in nasty weather. Woods shot 81 in the third round — 10 players failed to break 80 — for his highest score as a pro.