Pospisil was assessed a major penalty and a game misconduct late in the first period of Calgary’s 4-1 win on Tuesday.
After Flames goaltender Jacob Markstrom made a save and covered the puck, Marchand gave the goalie a few extra whacks with his stick. That quickly drew the attention of three Flames, including Pospisil.
Pospisil caught Marchand up high with a cross-check to the head area, and after a lengthy review, was ejected from the game with over two periods to go.
The referees also handed Marchand a two-minute penalty for slashing.
Pospisil was playing in his first game since Jan. 18 when he suffered an upper-body injury against the Toronto Maple Leafs. In 33 games this season, the rookie has four goals and 11 points.