Sundqvist is headed for surgery after sustaining a torn ACL in Monday's matchup with Vegas. He'll be reevaluated in six months.
Sundqvist is being evaluated for a lower-body injury Wednesday and will miss Thursday's game against Calgary.
Sundqvist signed a two-year, $3 million extension with the Blues on Thursday.
Sundqvist recorded an assist in Sunday's 7-2 win over the Canadiens.
Sundqvist scored a goal on two shots in Monday's 4-2 loss to the Flyers.
Sundqvist dished an assist in Monday's 2-1 OT road win against the Golden Knights.
Sundqvist posted an assist, one shot on goal and one hit in Saturday's 4-2 win over the Penguins.
Sundqvist inked a one-year, $775,000 contract with St. Louis on Wednesday, per Jeremy Rutherford of The Athletic.
Sundqvist (lower body) will not suit up Mony against the Stars, Michael Russo of The Athletic reports.
Sundqvist (lower body) is practicing Saturday in a non-contact jersey, Sarah McLellan of the Minneapolis Star Tribune reports.