Sundqvist appeared to collide with teammate Kyle Clifford in front of the Sharks' net with 1:07 remaining in the first period and was helped off the ice by Ryan O'Reilly, Sammy Blais and Blues Head Athletic Trainer Ray Barile.
After the game, Blues Head Coach Craig Berube said he did not have an update but that Sundqvist was scheduled to have an MRI.
Sundqvist has played in 27 games this season, posting four goals and five assists (nine points).