July 8th 2015: Rory McIlroy announced on Wednesday that he will be unable to defend his title at next week’s Open Championship at St. Andrews after suffering a ruptured ligament in his ankle.

"After much consideration, I have decided not to play in the Open Championship at St. Andrews," McIlroy said 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% healthy and 100% competitive. Thank you for all your support and best wishes."

McIlroy suffered the injury during a friendly game of soccer last Saturday. He was running on a synthetic grass field when his left ankle snagged the turf and rolled over, causing a total rupture of his anterior talofibular ligament, the major ligament that stabilizes the ankle, and associated joint capsule damage.

“We are naturally very disappointed that Rory will be unable to defend his title at St. Andrews next week,” The Open Championship said in a statement. “Rory will play in many more Open Championships and our primary concern is for his complete recovery. Everyone associated with The Open wishes Rory the very best as he looks to return to full fitness.”

Though McIlroy will not need surgery, there is no timetable for his return.

“Taking it day by day,” McIlroy’s manager said in an email. “Working hard in rehab.”

McIlroy’s absence marks the first time a player has not been able to defend at a major championship since Tiger Woods missed the 2008 PGA Championship at Oakland Hills after undergoing reconstructive knee surgery following his U.S. Open victory at Torrey Pines earlier that summer.

It is also the first time in more than six decades the reigning Open champion will not be playing. Ben Hogan did not play the 1954 tournament after winning a year earlier at Carnoustie.

McIlroy was replaced in the field by Scotland's Russell Knox, who will be making his Open debut.

Whether McIlroy will be able to defend his PGA title next month at Whistling Straits, which begins Aug. 13, remains to be seen. He also won last year’s World Golf Championships-Bridgestone Invitational, which will be played the week before.

Scottish golfer Richie Ramsay tore ligaments in his ankle in December of 2013. After hearing of McIlroy’s injury on Monday, he offered some insight.

"I had a full tear of ligaments in my ankle not long ago," Ramsay said via Twitter. "It takes a lot longer than you think to heal. 3 months til I played after tearing ligaments and even then getting my foot to work the right way was tough."

McIlroy and Jordan Spieth have won the last four majors, with Spieth winning the Masters and U.S. Open this year to rise to No. 2 in the world behind McIlroy. Spieth will arrive at St. Andrews as just the fourth player in golf history with a shot at the modern Grand Slam.

Spieth could also replace McIlroy atop the Official World Golf Rankings. Should he finish roughly seventh or higher at this week’s John Deere Classic and go on to win The Open Championship, the 21-year-old would move to No. 1.

"We want him back. Everybody does," Spieth said earlier this week. "It's unlucky, it's unfortunate, and I'm sure he's taking it harder on himself than anybody else. But I don't think he did anything wrong, it was just an unfortunate situation. And hopefully, he rebounds quickly and gets back right to where he was."