World number one Rory McIlroy will not return to action until he is 100 per cent fit after being forced to miss the defence of his Open Championship title at St Andrews next week.
McIlroy revealed on Monday that he had suffered a ''total rupture'' of the anterior talofibular ligament in his left ankle while playing football with friends.
And the 26-year-old confirmed on Wednesday that he would not be able to compete at the Old Course, where he carded an opening 63 - the lowest first round in Open history - in 2010.
''After much consideration, I have decided not to play in the Open Championship at St Andrews,'' McIlroy wrote on Instagram. ''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. I hope to be back on the course as soon as I can."
McIlroy's defence of both the Bridgestone Invitational in a month's time and the following week's US PGA Championship at Whistling Straits is also in serious jeopardy, with medical experts predicting he could face three months on the sidelines.
Next week's clash between McIlroy and Masters and US Open champion Jordan Spieth had been eagerly anticipated and Ryder Cup team-mate Graeme McDowell said: ''It's hugely disappointing, especially with him and Jordan and everything that's going on. It was looking a really exciting Open for all involved.
''No one would love to stop Jordan in his tracks next week more than Rory. With the fun rivalry going on and everything, he's going to be gutted. I saw the golf course last Saturday and I believed that Rory was rightly a favourite. I thought he'd get it done round there.''
Former US Open champion Justin Rose added: ''I would have been surprised if he was there given the initial diagnosis but it's a big shame for him and the tournament.''
McIlroy is the first player not to defend his Open title since Ben Hogan in 1954, Hogan having won the Claret Jug at Carnoustie in 1953 in his only appearance in the event.
A statement on the Open Championship Twitter account read: ''We are naturally very disappointed that Rory will be unable to defend his title at St Andrews next week.
''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.''