The previously undefeated fighter from Montreal will face unheralded Russian Denis Grachev (12-0-1) at the Bell Centre on Saturday night. The 12-round bout could be a first step in restoring Bute's tarnished reputation.
A win will set up a rematch on home soil with Froch, tentatively set for March 31.
''The only opponent in my head is Grachev,'' Bute (30-1) said Tuesday after a workout at the InterBox gym. ''This is a very important fight.
''I defended my title 10 times but this is the most important fight.''
The 32-year-old was considered among the world's top two or three super-middleweights before travelling to Froch's hometown of Sheffield, England, to make the 10th defence of the International Boxing Federation title he had held since 2007.
He got an exemption from his contract with the U.S. specialty channel Showtime, which wasn't interested in the bout, to face Froch and quiet detractors who said he never faced top contenders and would only fight in friendly environments in Quebec or his native Romania.
The doubters had a field day when the brawling Froch pounded Bute senseless in five rounds to take the title. Suddenly, the one-punch knockdown and near knockout he suffered a few years ago from Librado Andrade looked more like an omen than an accident.
Suddenly, Bute's chin and heart were being questioned.
''People ask how it happened, but it doesn't matter,'' he said. ''The damage is done and now we're looking forward.
''We'll learn from it.''
Bute took a month off after the loss before getting back to work. In training, the southpaw with the deadly left uppercut looked his old quick-handed self and was perhaps more business-like in his approach than before recent bouts.
''He's going to get hit again and he's going to have two choices — retaliate and get into the war or say 'It's too hard for me,' '' said Bute's trainer Stephan Larouche. ''But he's ready for this.
''He's against the wall and he feels it. And (Grachev) is a guy who is going to test him.''
The 30-year-old Grachev, a former kick-boxer based in San Diego, was on no one's radar until his April bout against previously unbeaten Ismayl Sillakh. The Russian was knocked down in the third round but got up to floor Sillakh and end the fight in the eighth to claim the minor NABF light heavyweight title.
That belt will be on the line against Bute, although at a catch-weight of 170 pounds.
''I'll put a lot of pressure on Bute and he won't be able to handle it,'' said Grachev. ''That's my style, I can't fight different.
''Froch spoiled my goal. I like to fight undefeated guys. But Bute is a strong fighter. I like fighting him. I think I'm going to win. I would like to visit England and fight Carl Froch. I think this will be a big step for my career.''
The bout is to be aired in the U.S. on Wealth TV and on pay-per-view in Canada.
Froch has his first title defence in two weeks against Yusaf Mack, but what may stand in the way of a rematch with Bute is another Montreal fighter. Adonis Stevenson won an elimination bout Oct. 12 that makes him the mandatory challenger to Froch.
The IBF would need to grant an exemption to let Froch fight Bute first. Stevenson's promoter Yvon Michel opposes an exemption.
The undercard also has some interesting bouts.
The 10-round co-feature has veteran Renan St. Juste (23-3-1) of Repentigny, Que., against American Allan Green (31-4). Green was once a top contender at both super-middleweight and light heavyweight but is coming off a loss to Mikkel Kessler, the former WBC champion who beat Froch in 2010.
Super-bantamweight Sebastien Gauthier (22-3) takes on former IBF champion Rodrigo Guerrero (17-4).
And Mikael Zewski (16-0), a 23-year-old light middleweight from Trois-Rivieres, Que., who was overlooked by Quebec-based promoters and fights out of Las Vegas, faces Mexican Cesar Chavez (20-2).