Rory McIlroy suffers ruptured ankle ligament while playing soccer

Rory McIlroy's bid to defend titles at each of the year's final two major championships might have reached a major hurdle this weekend.

On Monday, McIlroy announced that he's suffered a total rupture of his left ATFL, a ligament in his left ankle. He posted a photograph to Instagram with his leg in a boot as he balanced on crutches.

"Continuing to assess extent of injury and treatment plan day by day," the world's top-ranked golfer wrote. "Rehab already started. ... Working hard to get back as soon as I can."

He posted that the injury occurred while playing soccer with friends Saturday.

McIlroy was scheduled to play the Scottish Open this week as a tuneup for next week's Open Championship at St. Andrews. He remains listed in the field for both events.

The last time the Open was held at St. Andrews in 2010, he posted scores of 63-80-68-69 to finish in a share of third place.