The Avs lost 2-1 in overtime.
Hejduk left Sunday's 1-0 overtime win early in the first period after a collision with teammate Paul Stastny as they drifted into the Sharks' zone. He was helped off the ice and straight into the locker room.
The Avalanche also will be without center Kevin Porter for a second straight contest after he suffered an upper-body injury in Game 2.
The Sharks got one of their top offensive players back in Dany Heatley, who was held out Sunday with an unspecified injury.
The series is tied at 2.
The Associated Press contributed to this report.