The eighth-ranked Monfils, a U.S. Open semifinalist this year, has already qualified for the season-ending ATP finals in London next month. He is making his first appearance at the finals.
Tournament organizers said Friday that Spaniard Marcel Granollers has also pulled out of the Paris Masters, without giving a reason.
They will be replaced in the main draw by Ukrainian Illya Marchenko and Argentine Guido Pella.
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