World number one Rory McIlroy has revealed that he has ruptured ligaments in his left ankle during a football kickabout.

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McIlroy announced the news via Twitter, with an accompanying photograph on Instagram showing himself on crutches and wearing a protective boot.

The news comes less than a fortnight before McIlroy was due to defend his Open Championship title, although the Northern Irishman has not yet ruled himself out of the event at St Andrews. 

McIlroy tweeted: "Total rupture of left ATFL (ankle ligament) and associated joint capsule damage in a soccer kickabout with friends on Saturday. Continuing to assess extent of injury and treatment plan day by day. Rehab already started….. Working hard to get back as soon as I can."

McIlroy was also due to play in the Scottish Open this week to fine-tune his preparations for St Andrews but his participation in both must now be in serious doubt.

The 26-year-old won the Open at Royal Liverpool last year before going on to win another major title, his fourth, at the US PGA Championship.