Kopitar, the Kings' leading scorer, broke his right ankle after getting tied up along the boards and falling awkwardly in the second period. The injury comes less than week after Los Angeles saw second-leading scorer Justin Williams go down for the season with a dislocated shoulder.
Kopitar and Michal Handzus each scored a goal and Jonathan Quick made 20 stops for the Kings, who won their third straight and temporarily gained a two-point hold on fifth place in the Western Conference over Nashville.
Milan Hejduk tallied and Peter Budaj stopped 21 shots for the Avalanche.
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