The defenseman was injured in the second period of a 5-3 loss to the Edmonton Oilers on Friday. He has one assist in four games this season.
Vegas is also without defenseman Alec Martinez, who did not play Friday because of an undisclosed injury and is day to day, and forwards Max Pacioretty (lower body) and Mark Stone (lower body).
Pacioretty is week to week after blocking a shot in a 6-2 loss to the Los Angeles Kings on Oct. 14. Stone is out indefinitely after he was injured in that game.
"It is what it is," Vegas coach Peter DeBoer said about the injuries. "Everybody deals with it, and I'd rather deal with it now than later. We're going to use it to learn about our group."
Daniil Miromanov will replace Whitecloud in the lineup when the Golden Knights host the New York Islanders at T-Mobile Arena on Sunday (10 p.m. ET; NHLN, SN1, ATTSN-RM, MSG+, NHL LIVE). The 24-year-old defenseman will make his NHL debut.
"We want the best guy," DeBeor said. "I don't think we can be picky, especially with the number of injuries we have. We just need the best guy."
NHL.com independent correspondent Danny Webster contributed to this report
