Drouin was limited to only 27 games in 2019-20 after battling a series of injuries. The 25-year-old most recently played Feb. 25 and missed the Canadiens' final six contests with an ankle injury before the league suspended the season on March 12.
The 6-foot winger tallied seven goals and 15 points while averaging 15:42 of ice time this season.
NHL commissioner Gary Bettman announced the 24-team, two-city playoff format Tuesday.
The Canadiens, who were all but eliminated from postseason contention under the traditional format, own the 12th and final Eastern Conference playoff spot under the restructured conference-based seeding. Montreal will play the fifth-seeded Penguins in a best-of-five qualifying series with the winner advancing to the 16-team bracket.