McIlroy had indicated after a disappointing 22nd-place finish in the PGA Championship that he might sit out the rest of the year.
He said the effects of a broken rib suffered early in the season continued to hinder his practice and had led to back spasms.
But the 28-year-old decided to take a stab at defending his FedEx Cup crown after meeting with fitness adviser Steve McGregor in Belfast, the Daily Telegraph reported.
McIlroy won the second playoff event and the Tour Championship to clinch the FedEx Cup last year.
Just like last year, he has not won a title prior to the playoff series.
This season's series opens with the Northern Trust in New York next week, followed by the Dell Technologies Championship in Boston a week later.
After a week off, they series resumes with the BMW Championship before the top 30 in the FedEx Cup standings advance to the Tour Championship.
McIlroy seemed confident he would be playing through the BMW Championship when he posted a note to fans on Twitter on Friday — urging them to enter a contest to win a chance to play 18 holes with him at the tournament in Illinois.
COMMENTS
Comments are moderated and generally will be posted if they are on-topic and not abusive.
For more information, please see our Comments FAQ