Analyst house Lazard Capital Markets thinks World of Warcraft could lose between 900,000 and 1.6 million players following December's Star Wars: The Old Republic launch.
A recent survey conducted by the firm in conjunction with Peanut Labs found that over 50 percent of 381 respondents have grown tired of Blizzard's game.
Half said they cent plan to buy The Old Republic, while a further 38 percent declared an interest in the title, Develop reports.
Worldwide active subscribers to World of Warcraft declined by 800,000 to 10.3 million in the three months ended September 30.
According to Lazard, 33 percent of those polled said the release of WoW's fourth expansion, Mists of Pandaria, would be enough to make them re-subscribe to the MMO.
The Old Republic developer BioWare said in June that it expects its game "will more than compete" with WoW following "a fantastic response" from beta testers.