He returned for the Lightning to start the third period.
Stamkos went down while battling with Brandon Prust and then started sliding down the ice when he came across Emelin's knee. It connected with the back of Stamkos' head and the Bolts captain immediately went down in a heap (GIF via @MyRegularFace).
After some on-ice attention, Stamkos was able to get up -- after a stumble -- and skate off the ice under his own power but he was taken to the dressing room and didn't look to be in the best of sorts.
This hit to Stamkos came less than a minute after the Lightning had a go-ahead goal denied on a very dubious goalie interference call. It could very well go down as one of, if not the worst 30 seconds in Tampa Bay Lightning history
Stamkos had 25 goals in just 37 games this season, a season limited by a broken leg in early November after a collision with the goal post in Boston.