Therrien did not rule out Price rejoining the Canadiens for their game at the Ottawa Senators on Saturday. Montreal plays its home opener against the Pittsburgh Penguins on Tuesday.
"There's a chance he'll join us Friday in Ottawa, but he'll have to be healthy," Therrien said. "It's unfortunate. We would have liked him to be there for our opening game, but like we say, 'What can you do?"
Price, who won the Hart and Vezina trophies in 2014-15, helped Team Canada win the World Cup of Hockey 2016 in September, and played one preseason game for Montreal.
"Obviously it hurts losing Carey, he's one of the best in the world," said defenseman Shea Weber, who will make his Canadiens debut Thursday. "We'll get there when he's healthy and ready to go, but for the most part we're excited for [Thursday] and looking forward to getting the first game going."
Goalie Al Montoya will start. The 31-year-old signed a one-year contract with Montreal as a free agent on July 1 after going 12-7-3 with a 2.18 goals-against-average and .919 save percentage in 25 games with the Florida Panthers last season.
Montoya beat out Mike Condon for the backup job on Monday. The Pittsburgh Penguins claimed Condon on waivers Tuesday.
"The start was going to come sooner or later and it's here now, and I'm excited, I'm ready for it," Montoya said. "This is what I've been preparing for and I'm looking forward to stepping on the ice with this group."
The Canadiens will recall goaltender Charlie Lindgren from St. John's of the American Hockey League to be Montoya's backup in Buffalo.
Injured defenseman Jeff Petry (knee) also will not play Thursday.
"His rehab is going very well and he will make the trip with us," Therrien said. "We'll see how he handles practice on Friday."
