Ankle injury could keep Rory McIlroy from defending two major titles

World No. 1 Rory McIlroy might miss title defenses in the final two majors of the season with an ankle injury he suffered while playing soccer with friends.

In a shocking post Monday on Instagram that felt like a kick in the stomach for the golf world, McIlroy is on crutches and wearing a walking boot on his left ankle. He wrote that he sustained a "total rupture" of an ankle ligament and the associated joint capsule on a soccer pitch near Belfast, Northern Ireland.

"Continuing to assess extent of injury and treatment plan day by day," McIlroy said in the post. "Rehab already started. … Working hard to get back as soon as I can."

McIlroy's manager, Sean O'Flaherty, confirmed the winner of four majors and three worldwide titles this year is definitely out of this week's Scottish Open at Gullane.

McIlroy, however, has not ruled out playing in the British Open on the Old Course in St. Andrews, Scotland, beginning July 16, according to O'Flaherty. He will have daily tests on the ankle and start rehab, his manager said.

McIlroy, 26, had been gearing up to defend his titles in the British Open and the PGA Championship. McIlroy went wire-to-wire at Royal Liverpool in Hoylake, England, last year to win the Open and pulled out a 1-stroke victory in the fading light at Valhalla Golf Club in Louisville.

Now, however, his anticipated showdown with world No. 2 Jordan Spieth on the Old Course is in jeopardy. Spieth, who is playing in this week's John Deere Classic in Illinois, will try to win the third leg of the Grand Slam in St. Andrews after capturing the Masters and the U.S. Open.

"Wishing Rory the best and a speedy recovery," Spieth said in a statement released by his agent. "It's unfortunate, and you never want to see a fellow competitor injured. I hope he will be back very soon."

McIlroy finished in a tie for third in the 2010 British Open at St. Andrews after opening with a 63. An 80 during a wind storm in the second round ruined his chances for the Claret Jug, but he shot 69-68 on the weekend. McIlroy also secured his European Tour card in 2007 in the Dunhill Links, which is played on three courses including the Old Course.

In his post, McIlroy referred to his ATFL (anterior talofibular ligament), one of three ligaments around the ankle. Dr. James Gladstone, co-chief of sports medicine at the Icahn School of Medicine at Mount Sinai Hospital in New York, said the rupture isn't in and of itself "a big deal."

"It isn't career threatening or necessarily time threatening. You could have a sprain and within two weeks be going strong," Gladstone said. "At other times it could ultimately require surgery. Typically most people who sprain their ankles don't need surgery. Only if people suffer recurring sprains would surgery be required."

Gladstone said the typical treatments include rest, ice and anti-inflammatory treatment.

"Therapy from the outset with modalities such as electrical stimulation or ice baths can be helpful, too," he said. "After the swelling and pain is controlled you can start the strengthening program, strengthening the tendons around the ankles. Rehab can be as quick as 10 days to two weeks or as long as four to six weeks."