Marchand had already made trips to the dressing room throughout the game for a leg injury. He had been back on the ice for just minutes before Volchenkov came up and threw one of the more blatant elbows to the head you'll see.
No attempt to play the puck, intent was pretty clear and the head was the principal point of contact. Add in the fact that he was suspended two years ago for elbowing, that's a suspension for sure. The refs recognized it as such and slapped Volchenkov with a five-minute major and a game misconduct. Marchand has not returned to the game.