The 29-year-old Soderberg had 13 goals and 31 assists last season. He adds depth to a Colorado front line that already includes Nathan MacKinnon, Matt Duchene, Gabriel Landeskog, Alex Tanguay and Jarome Iginla.
A second-round pick of St. Louis in 2004, the 6-foot-3, 216-pound 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.