In fact, he started the season on MacKinnon and Rantanen's line, but his coach seems to be getting tired of it already. He was demoted to the second line for Tuesday's game.
It's not too shabby to be paired with Artturi Lehkonen and Ryan Johansen, but even there, it's not guaranteed. Tomas Tatar took his place a few times during the game.
In short, in just three games, Drouin went from playing on a line with two 100-point scorers to possibly being on the third line in the next game. It's safe to say that it's quite disappointing in his case.