'I've probably played an extra couple tournaments too much and I have learned from the last few years,' the Ulsterman explained to reporters. 'That's why I'm cutting back my schedule even further from next year.'
Including next week's season finale in Dubai, McIlroy will have played in 24 events this year in addition to two exhibition events - the Turkish Airlines World Golf Final and the Duel at Jinsha Lake with Tiger Woods. Last year, he played in 22 events as well as four exhibitions.
'I now look back over the last couple years and wonder why did I stretch myself so much,' he added.
Having wrapped up the Race to Dubai title with a third-place finish at last week's Barclays Singapore Open, McIlroy explained that a dip in on-course performance may have been inevitable.
'When you achieve something that you want to achieve so bad, like the Race to Dubai, there is a letdown considering there are still two events remaining,' he told media members.
As the 2012 season winds down - one in which he won a major, ascended to the top of the OWGR and captured the money titles on both the PGA and European Tours - McIlroy notes that this year may have taken a larger toll than he anticipated.
'I'm not sure if the energy in trying to sew up the Race to Dubai and competing in the FedEx Cup has taken more out of me than maybe I thought,' McIlroy commented. 'Because while I am feeling OK physically, mentally I feel really tired.'