Bute (30-1, 24 knockouts) is coming off a one-sided loss in May to Carl Froch that cost the Montreal fighter his International Boxing Federation super-middleweight title.
Like Froch, Grachev (12-0-1, 8 KOs) is a heavy-handed brawler who will test the chin that let Bute down against Froch. The Englishman stopped Bute in only five rounds.
''We chose Grachev for his abilities in the ring,'' Stephan Larouche, Bute's trainer, said in a statement ''I am convinced that his punching power and inside brawler style will be a good test for Lucian.''
Grachev's minor NABF light heavyweight (175-pound) title will be on the line in the 12-round bout. They will fight at a mutually agreed weight of 170 pounds, as Bute wants to remain in the super-middleweight (168-pound) division.
The San Diego-based Grachev is coming off an eighth-round knockout of light heavyweight prospect Ismayl Sillakh.
''I am very happy that this fight is signed,'' said Bute. ''I can't wait to see my fans again and to fight in front of them at the Montreal Bell Centre.
''This fight will be the first step of my goal to reconquer the IBF super middleweight belt.''
Bute's fight with Froch in England had a rematch clause and they are expected to meet again in Montreal some time in 2013.