The 39-year-old goalie was placed on injured reserve Sunday.
Luongo left the Panthers' season-opening 2-1 shootout loss to the Tampa Bay Lightning on Saturday at 12:21 of the second period after he was injured during a scramble in front of Florida's net. Panthers defenseman Mark Pysyk and forward Frank Vatrano collided, and Vatrano fell on Luongo's right leg.
Luongo, who made 13 saves, needed assistance getting off the ice. He was replaced by James Reimer, who made 15 saves on 16 shots.
"It could have been worse," Boughner said. "It was a freak accident. It wasn't like he streched out and pulled it or twisted it that way. Someone fell on him, and that happens during the game.
"He's looks bummed out today, naturally. I think he's worked hard and had a great summer. He looked good the other night, comfortable in there. It's unfortunate. Now he has to get some rehab and get back to practicing again, and get his composure and his game back. He's dealt with it many times before, so I'm not worried about that. We need to play some good games here, a good stretch of hockey, while he's not going to be with us."
Reimer likely will start for the Panthers in their home opener, against the Columbus Blue Jackets on Thursday (7 p.m. ET; FS-F, FS-O, NHL.TV).
"In his absence, it's just win some hockey games," Reimer said. "That's what we train for all summer to do."
Luongo is in his 18th NHL season. He was 18-11-2 with a 2.47 goals-against average and .929 save percentage in 35 games in 2017-18.
Goalie Michael Hutchinson was recalled from Springfield of the American Hockey League on an emergency basis Monday. Hutchinson, 28, made 44 saves in a 3-2 shootout loss to Wilkes-Barre/Scranton on Saturday. He agreed to terms on a one-year contract with the Panthers on July 1 after going 43-39-11 with a 2.65 GAA and .910 save percentage in 102 games with the Winnipeg Jets.
"I'm just coming in here looking to work hard and, if I get the chance, help the team win games," Hutchinson said.
