Fleury, a 30-year-old wing, has spent his entire NHL career with the Flames, winning a Stanley Cup with the team as a rookie in 1989.
He has 30 goals and 39 assists this season. He has said repeatedly he wouldn't sign a new contract until testing the free-agent market this summer.
Avalanche spokesman Jean Martineau said Fleury would arrive in Denver on Sunday.
Fleury became the Flames' career scoring leader last Friday. In 791 games, he has 364 goals and 466 assists for 830 points.
Earlier this year, Calgary's Cory Stillman said Fleury is "by far our greatest player and he's proving it now."
Dingman, an enforcer, has played only two games this season. Corbet, 25, has eight goals and 14 assists in 53 games. Belak, a 22-year-old prospect, has no points with the Avalanche this season.
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