Blackhawks forward Marian Hossa had to be helped off the ice after Vancouver winger Jannik Hansen hit him in the back of the head with his left forearm.
The play occurred early in the third period. Hossa, who scored a pair of goals in the second, stayed down for a short stretch as the sellout crowd at the United Center booed Hansen. Hossa eventually got up and went to the bench as Hansen made his way to the penalty box to serve his 2-minute penalty for roughing.
The Blackhawks went on to beat the Canucks 4-3.
Coach Joel Quenneville said he saw Hossa after the game and said he "seemed OK."
Chicago was already without defenseman Brent Seabrook and goalie Corey Crawford.
Seabrook is out with a lower-body injury after he was hurt in Sunday's 3-2 victory over the Los Angeles Kings. Crawford has been sidelined with an upper-body injury since he had 31 saves in a 3-2 shootout loss to Anaheim last Tuesday.
Hossa last year was injured after being hit by Phoenix's Raffi Torres in the first period of Game 3 of their opening-round playoff series.