In the off-season, Stewart signed a two-year contract with the Avalanche, and began the 2010–11 season with Colorado. On October 28, 2010, he earned his second career hat trick in a 6–5 Avalanche win over the Calgary Flames, scoring all three goals against Henrik Karlsson. On February 19, 2011, the Avalanche traded Stewart, Kevin Shattenkirk and the Avalanche's second-round draft pick in 2011 to the St. Louis Blues for Erik Johnson, Jay McClement and the Blues' first-round pick in 2011. He finished with 13 goals and 30 points in 36 games with Colorado.