Coach Pete DeBoer announced the decision on Thursday, with the Golden Knights preparing to play the Buffalo Sabres in the second stop of a four-game road trip. DeBoer didn't provide details on the injury except to say it's not related to the upper-body injury which led to Lehner missing five games late last month.
Lehner is 2-2 since his return and was coming off a 19-save outing in a 2-1 loss at Philadelphia on Tuesday.
Overall, he has a 21-15-1 record since taking over as the starter after Vegas traded Marc-Andre Fleury to Chicago last offseason.
The injury is the latest for the Golden Knights, who sit third in the Pacific Division standings and are in a tightly contested playoff race. The team has five players on injured reserve, including captain Mark Stone and defenseman Alex Martinez.
DeBoer said forward Reilly Smith would not play against Buffalo.