|US PGA Championship|
|Venue: Valhalla, Kentucky Dates: 7-10 August|
|Coverage: Daily reports on BBC Sport website, live text and radio commentary of the last two days on the BBC Sport website, BBC Radio 5 live sports extra and BBC Radio 5 live|
Tiger Woods couldn't disguise his agony as his comeback from back surgery came to its abrupt end at the WGC Bridgestone Invitational in Ohio.
Witnessing his painful attempt to change his shoes in the Firestone car park in the wake of his buggy ride from the ninth fairway, it was hard not to fear for his golfing future.
This is a massive setback for the former world number one, who was playing only his 10th competitive round since back surgery in March.
The 38-year-old was a frail figure as he departed. Dismiss any notion that he cured his back problems with the microdiscectomy he underwent on 31 March to alleviate a pinched nerve.
Woods first suffered back spasms during the Barclays tournament in New Jersey last September. Although he completed the 2013 calendar, the injury resurfaced when he withdrew from the Honda Classic in early March.
|What is microdiscectomy?|
|In a microdiscectomy or microdecompression spine surgery, a small portion of the bone over the nerve root and/or disc material from under the nerve root is removed to relieve neural impingement and provide more room for the nerve to heal.|
|A microdiscectomy is typically performed for a herniated lumbar disc and is actually more effective for treating leg pain than lower back pain.|
The 14-time major champion finished the WGC event at Doral the following week but soon after was told he needed surgery to repair the problem.
It cost him his place at the Masters and US Open, and although Woods returned to action in Washington at the Quicken Loans National at Congressional on 19 June, he was clearly rusty and he missed the cut.
Woods didn't play again until the Open, where he played all four rounds but never contended.
This week in Ohio his rounds became progressively worse with scores of 68, 71 and 72. During his third round he swore at a cameraman who he felt was getting too close to him.
On the second hole of his final round Woods faced an awkward shot from the top of a fairway bunker. "When I hit my second shot I fell back into the bunker. I just jarred it and it's been spasming ever since," he said.
"It's the whole lower back. I don't know what happened."
|Woods' major victories|
|Masters (4)||1997, 2001, 2002, 2005|
|PGA Championship (4)||1999, 2000, 2006, 2007|
|US Open (3)||2000, 2002, 2008|
|Open Championship (3)||2000, 2005, 2006|
Given the apparent extent of his pain it is hard to imagine Woods being fit for the final major of the year, the US PGA, at Valhalla next week. Indeed, his season may well be over.
US Ryder Cup captain Tom Watson has been considering whether to pick the current world number 10 for this September's match at Gleneagles. That decision may have been taken out of his hands.
It has been a calamitous week for the American team following the withdrawal of Dustin Johnson from competitive golf to confront "personal challenges".
Given the debilitating nature of recurring back problems, it doesn't feel like an exaggeration to say the challenge facing Woods now is one of trying to save his career.