Rainbow Six: Patriots is rumoured to have been cancelled after major US retailer GameStop removed the title from its website and stopped accepting pre-orders.
IGN noticed that the listing had been removed from the site earlier today, and cites a source "with intimate knowledge of the retailer" as saying GameStop "actively flicked a switch" to remove the game from its website, suggesting the delisting is not accidental.
The site also points out that it's "exceedingly rare" for GameStop to delist a game that has previously featured on the cover title of sister magazine Game Informer.
Other retailers, however, still seem to be accepting pre-orders. GAME still carries a tentative 2013 release date for the title.
Rainbow Six: Patriots was first announced by Ubisoft in November 2011 for release this year, but little has been seen since its reveal.
In November 2012, however, CEO Yves Guillemott told Polygon that the game was still in development, and suggested that the title could have shifted to next-gen consoles.
"The only thing I can say is that we have a good team working on it, and it's really looking good," Guillemot said. "So when it will come, it will surprise the industry."
The game did not feature by name on Ubisoft's FY14 release schedule revealed during its financial earnings call earlier this week.
VideoGamer.com has contacted Ubisoft for comment.