Drouin, 26, is sidelined indefinitely with an upper-body injury.
The eight-year veteran also remains at home after coming into contact with someone who tested positive for COVID-19.
Drouin returned to the Habs' lineup on March 19 after recovering from a wrist injury that forced him to miss 22 games.
The Sainte-Agathe, QC native has 20 points (6 goals, 14 assists) in 34 games this season.
The Canadiens also announced that forward Brendan Gallagher is sidelined for one week with a lower-body injury.
