Defending champion Rory McIlroy is a major doubt for next week's Open Championship after suffering a serious ankle injury playing football.
The European Tour has confirmed McIlroy has withdrawn from this week's Scottish Open after the world number one revealed he suffered a "total rupture" of a ligament during a "kickabout" with friends on Saturday.
The 26-year-old posted the news of the injury on his Instagram account with an accompanying photograph showing him on crutches and wearing a protective boot on his left foot.
McIlroy is still to be fully assessed and has not yet ruled himself out of the Open at St Andrews, which begins on July 16, but his participation must be in jeopardy.
McIlroy wrote: "Total rupture of left ATFL (ankle ligament) and associated joint capsule damage in a soccer kickabout with friends on Saturday. Continuing to asses extent of injury and treatment plan day by day. Rehab already started..... Working hard to get back as soon as I can."
McIlroy, who won the Claret Jug at Royal Liverpool last year, was the favourite for St Andrews and much had been made of a potential rivalry with Jordan Spieth, winner of the year's first two majors.
A spokesman for the player said McIlroy had not yet ruled out competing but it is understood he will undergo further scans in the coming days. A full prognosis will become clear in due course.
Recovery from such injuries in athletes, if as severe as McIlroy has suggested, take months or even require surgery. The fact the injury is to the left ankle is also significant for a right-handed player as that joint bears most of the pressure through the swing.
European Tour professional Richie Ramsay tweeted: "I had a full tear of ligaments in my ankle not long ago. 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."
Should McIlroy be sidelined and be out of action for more than a month, he could also be doubtful for next month's US PGA Championship, the year's final major and another title he currently holds.
Paul McGinley, McIlroy's captain at last year's Ryder Cup, heard the news as he visited Wimbledon on Monday and expressed disappointment at the prospect of him not featuring at St Andrews next week.
McGinley said: "I'm sure he'll be very disappointed. I'd like to find out a little bit more because sometimes these injuries can settle down very quickly. But it'll be a blow not just for Rory but a blow for the game as a whole."