NHL Player Safety deemed the collision to be "a forceful hit from behind on a defenseless player no longer in possession of the puck." It marks the first suspension of Killorn's career.
Nelson was initially shaken up and forced to leave the game, but he later returned after passing concussion protocol.
Killorn plays a top-six role and posted career highs in goals (28) and points (49) in 68 games this season, so his presence in Game 3 will be missed.
Tampa Bay leads the series 2-0.