LONDON — Rory McIlroy will not defend his British Open title at St Andrews next week after announcing Wednesday he did not want to risk further damage to the ankle ligaments he ruptured playing football last weekend. His presence at the spiritual home of golf had looked extremely doubtful after he suffered the injury in a kickabout with friends and posted a picture of himself wearing a protective plastic boot. "After much consideration I have decided not to play in the Open Championship at St. Andrews," the Northern Irishman wrote on his Instagram account. "I'm taking a long-term view of this injury and, although rehab is progressing well, I want to come back to tournament play when I feel 100 percent healthy and 100 percent competitive." The 26-year-old is the world No. 1 and has won four major titles, the 2011 US Open, the 2012 PGA Championship and, in 2014, the British Open and the PGA Championship. His potential showdown with double major winner Jordan Spieth was expected to be the highlight of the Open but the American will now start the tournament as the favorite. Ben Hogan in 1954 was the last British Open champion who did not defend. Hogan, who was nearly killed in an automobile accident in 1949, won the only British Open he played in 1953 at Carnoustie. "We are naturally very disappointed that Rory will be unable to defend his title at St. Andrews next week," the R&A said in a statement. "Rory will play in many more Open Championships and our primary concern is for his complete recovery." He was replaced in the field by Russell Knox, who grew up in Inverness in the north of Scotland and will be making his Open debut. Spieth will have a chance to replace McIlroy at No. 1 in the world if he were to win at St. Andrews. — Agencies