The 28-year-old first sustained the problem at the start of the year and he has been forced to spend two lengthy periods in recovery.
McIlroy is currently preparing for the final day of the US PGA Championship but is not in contention at Quail Hollow after a disappointing third-round 73 left him at four-over-par.
The Northern Irishman says he will assess his options after the major and has hinted he could take some more time off to get back to full fitness.
McIlroy said: "It's not a factor when I'm out on the course, but it's a factor off the course in terms of how much time I can practice.
"It's catch 22 because I want to play and I can play, but I can't put the practice in that I need to to get myself up in contention.
"We'll see where we go from here. I'll play tomorrow and assess my options for the rest of the year. I've still got a few big tournaments left, so it's a question of whether I play in all of them or take some time off to get 100 per cent healthy."