The right winger will be out for a second straight game with a lower-body injury.
Additionally, Jake Allen will line up between the pipes for a second consecutive game.
St. Louis will make defensive changes, brining Johnathan Kovacevic in the lineup and scratching Jordan Harris and Chris Wideman. Rem Pitlick will also return to the lineup. The forward was alongside Jake Evans and Michael Pezzetta on the fourth line during Saturday’s morning skate.
In 22 games this season, Gallagher picked up three goals and five assists.