In a test version of "Warlords of Draenor," a futuristic character named Robin emerges from a lamp to quote two lines from Disney's "Aladdin" genie, who was voiced by Williams.
It was a game devotee who announced the find on fan site Wowhead.
The fan also gave details of other apparent tributes to Williams: a character in suspenders like Williams' Mork from the sitcom "Mork & Mindy" as well as a woman who resembles Mrs Doubtfire, from the 1993 movie in which Williams cross-dressed as an elderly nanny.
According to specialist website The Verge, other tributes may appear in the final version of the game, which comes out November 13.
Blizzard Entertainment did not immediately respond to a request for comment.
But three days after the actor's death by apparent suicide, Blizzard had said it would memorialize the beloved actor in the game.
".@robinwilliams Thank you. You gave us so much joy in our lives, and we hope you enjoyed your time in our world. We'll see you in-game," they wrote on the @Warcraft account.
The actor's love of video games was evident in the choice of his daughter's name: Zelda, in reference to the Nintendo classic "The Legend of Zelda."
The death of Williams, one of Hollywood's brightest stars, sparked worldwide mourning. He suffered from severe depression and early signs of Parkinson's disease.
