Soderberg, whom the Avalanche picked up Thursday from Boston for a sixth-round pick in the 2016 NHL draft, was set to become an unrestricted free agent on July 1.
The 29-year-old had 13 goals, 44 points and a plus-10 rating last season. Soderberg also finished tied for second on the Bruins with five power-play goals.
The six-foot-three, 216-pounder will add depth to a Colorado front line that already includes Nathan MacKinnon, Matt Duchene, Gabriel Landeskog, Alex Tanguay and Jarome Iginla.
"He is a solid two-way forward who is big and strong on the puck," Avalanche general manager Joe Sakic said of Soderberg in a statement released by the team. "He is versatile, can play centre or wing, and his addition will also benefit our power play."
A second-round pick of St. Louis in 2004, Soderberg played in Sweden before joining Boston toward the end of the 2012-13 season. The Bruins acquired him from the Blues in 2007.
Soderberg has 29 goals in 161 career NHL games. He also has one goal in 14 playoff contests and earned just over a $1 million US last season.
Colorado's acquisition of Soderberg adds to the curious case of centre Ryan O'Reilly, who is entering the final year of his contract and has yet to sign an extension. The 24-year-old, who is due $6 million US next season, could be on the way out before Friday's first round of the draft.