The forward was injured blocking a shot in a 6-2 loss to the Los Angeles Kings on Thursday. He is tied for the Vegas lead with three points (two goals, one assist) in two games this season.
"[Pacioretty] took an innocent shot," Vegas coach Peter DeBoer said Saturday. "Just one of those things."
Pacioretty was second on the Golden Knights last season with 51 points (24 goals, 27 assists) in 51 games, and scored 11 points (five goals, six assists) in 13 Stanley Cup Playoff games.
Mark Stone sustained a lower-body injury Thursday and is day to day. The forward has three assists in two games this season after leading the Golden Knights in assists (40) and points (61) in 55 games last season. He scored eight points (five goals, three assists) in 19 playoff games.
Forwards Nicolas Roy, Brett Howden and William Carrier are skating and could return to practice Monday. Roy and Howden each began the season on injured reserve with an undisclosed injury, and Carrier missed the first two games with a concussion.
DeBoer said they could compete to fill Pacioretty's spot in the lineup.
"I don't want to put a ceiling on anybody," DeBoer said. "You talk to the guys in the top six, and I think sometimes you'd be surprised -- I get surprised sometimes -- at names when you ask them, 'Who do you think would be a good fit with guys out?' Will Carrier's name comes up, Nic Roy's name comes up. I don't think we're against anything. This is an opportunity for whoever we stick in here to take the ball and roll with it. At the same time, those bottom-six roles, those are difference-making lines."
The Golden Knights next play at home against the St. Louis Blues on Wednesday (10 p.m. ET; TNT, TVAS).
NHL.com independent correspondent Danny Webster contributed to this report
