Sedin was hurt in the second period as he collided with Ottawa defenceman Marc Methot.
Methot's elbow appeared to hit or come close to Sedin's head as the Canuck went down in a corner. But Sedin also held his leg in apparent pain.
No penalty was called on the play as the Senators took the puck back up the ice and had two scoring chances.
Sedin was helped by two trainers as he walked from the Canucks bench to Vancouver's dressing room.