Houser's unavailability makes it unclear who will start or even serve as Buffalo's backup on Saturday, when the team opens a three-game western road swing at Arizona.
Season opening starter Craig Anderson and backup Dustin Tokarski are traveling with the team. But they have yet to be cleared to play, leaving open a possibility the Sabres will have to sign another goalie.
Anderson resumed skating with the team this week after missing 32 games with an upper body injury. Tokarski has missed 20 games while recovering from COVID-19.
Meantime, Ukko-Pekka Luukkonen (lower body) and Malcolm Subban (upper body) have each missed seven games since they were hurt in a 6-1 loss to Tampa Bay on Jan. 11.
Houser was essentially considered the Sabres de-facto starter after the NHL on Wednesday suspended Aaron Dell for three games for a body check that injured Ottawa rookie Drake Batherson on Tuesday.
The Sabres had only signed Houser to an NHL contract two weeks ago after he was playing on a minor league deal in the team's farm system.