Speaking at The Tour Championship in Atlanta, the 35-year-old tied for ninth place with a closing 66.
The four-time major winner had a great start to the year when he won the Dubai Desert Classic. Other notable victories included his May victory at the Wells Fargo Championship.
In June, he finished second in the US Open at Pinehurst, where Bryson DeChambeau won thanks to a late collapse, but in July, he missed the cut at the Open Championship at Troon.
Representing Team Ireland in the Olympics in Paris, McIlroy finished in joint fifth place.
I felt like I hit a bit of a wall sort of post-US Open, and I still feel a little bit of that hangover, so it’s been a long season, and I’m just going to have to think about trying to put in a few additional breaks here and there next year and going ahead, McIlroy said.
