Duchene, who had an MRI on Sunday, suffered the injury on his first shift of Saturday's 3-2 win over the Sharks. He collided knee-to-knee with teammate Jamie McGinn and made it back to the bench on his own power but didn't return to the game.
The 23-year-old leads the team in points (70) and assists (47), and his +8 rating was the best of his five-year career.
The Haliburton, Ontario, native won a gold medal with Team Canada in Sochi.
Colorado (47-21-6), which has won three in a row, will likely be without Duchene through the first round of the playoffs, which begins on April 16. The Avalanche clinched their first playoff berth since 2010 on Saturday. MUIR: Today's must-read NHL stories