The Irishman played through the pain in losing a play-off to Graeme Storm at the BMW SA Open yesterday after revealing on Friday morning he had considered pulling out of the event due to the problem.
McIlroy initially cited the problem as suspected fatigue after an off-season that has seen him hit a lot of balls in practice trying to decide on new equipment after former supplier Nike decided to stop producing clubs last year.
But the world number two will now undergo a scan today to make sure the problem is nothing more sinister after playing in Johannesburg with his back taped up and taking anti-inflammatories.
American stars Dustin Johnson and Rickie Fowler - the defending champion - will be playing in Abu Dhabi and it would be a big blow for McIlroy to miss an event that has seen him finish outside the top three just three times in nine appearances.
“I am going for a scan tomorrow,” he told the European Tour’s official website. “I fly to Dubai tonight and then will go for an MRI tomorrow just to see what’s up with this joint in my back.
“It was manageable this week with tape and a few pills so I am fine but first and foremost I have to get fully fit and healthy again and hopefully I’ll be alright to play next week.
“We will see what happens but like I said, it is manageable with the tape and a few anti-inflammatories but it’s not 100%.
“Part of me really wants to make this week because there is so much to play for but at the same time there is so much to play for over the whole season and I don’t want to jeopardise long-term goals for short-term gain.
“Hopefully I’ll be good to go.”
Eighty-three days after losing his European Tour card by €100, Storm was given a reprieve when Patrick Reed failed to play enough events to join the Tour and he made the most of his second coming in Johannesburg.
Starting the day three shots clear of the world number two, he almost buckled under the heat as McIlroy made five birdies in a final-round 68.
But McIlroy’s bogey on the par-three 17th teed up a play-off which the Englishman took.
He held his nerve to sink a close-range putt after McIlroy had finished the first time they went back up the 18th hole, but when McIlroy drove wildly the second time, he had a chance.
His first shot was not ideal either, though, following McIlroy into the rough, and back they went again.
The third time out, McIlroy’s second shot on the par-four was a poor one, falling short of the green, and a 45-foot putt from Storm that skipped just past allowed him to take a par.
And when McIlroy failed from seven feet, the title was Storm’s which was his second European Tour title and first since he won the French Open in 2007.
“I am speechless. It’s been incredible and I can’t quite believe it,” he said.
“This is a dream come true, especially after what happened to me last year with my card and everything. I really took a lot from that experience and told myself to try and grasp the opportunity of getting my livelihood back with both hands and I have done that this week.
“It’s an unbelievable feeling. I hung in there today and didn’t play my best stuff but I knew if I could hang in there that I might get my chance and thankfully it came.
Storm picked up £143,000 as a result of the win.