McIlroy only has to finish in the top 10 at the Singapore Open this week to clinch the Race to Dubai as he is $978,000 in front of the second-place Hanson.
Poulter came from four strokes back to win the HSBC Champions in China by two shots on Sunday, rising from 13th to fourth in the money order after capturing his second WGC title.
All five players under McIlroy are sitting out the tournaments in Singapore and Hong Kong.
Singapore Open organizers were holding an invitation for Hanson but he's cited tiredness and has returned to his Florida home.
"I've been on the road three weeks now since playing the India Open, and that's a long enough time to be away from my young family and they're more important," the Swede said. "It's disappointing that it won't sort of add spice to these next two events but then given the season I've had, winning the KLM Open, playing in a winning Ryder Cup team and beating Rory last week in Shanghai [the BMW Masters] to win three out of four, I have to be very happy."
"In the bigger picture, I still have plenty of years to win the Race to Dubai and besides, given the way Rory has played this year, I feel as though he deserves to end the year No. 1.
McIlroy arrived in Singapore on Monday night for his first appearance in the co-sanctioned event.
Also back home in Orlando is Poulter and Rose. Poulter plans to play in the Australian Masters next week, when the Hong Kong Open will be held.