Woods underwent surgery to remove a pressurised disc fragment after feeling discomfort during the PNC Championship in December.

The 45-year-old announced the news on social media on Tuesday but McIlroy said: "I've known for a while. He had it on the 23rd of December.

"In his words it was a small procedure. Obviously any time you are being cut into you try to avoid that as much as you can, but he was back on his feet the next day so I don't think we can read too much into it.

"I think they were just trying to clean a couple of little bits up. Obviously he won't be playing for the next couple of months but he should be back for the Masters, if not before that, so I think he'll be just fine."

Woods underwent spinal fusion surgery shortly after the 2017 Masters, but defied the odds to win his fifth green jacket at Augusta National two years later.

"He won the Masters with four back surgeries so there's not much he can't do," McIlroy added ahead of this week's Abu Dhabi HSBC Championship.