With 27 games left in the regular season and the President's Trophy -- given to the team with the best record in the NHL -- within their grasp, now is not the time for the Bruins to be easing up.

So coach Bruce Cassidy decided Tuesday night it was time to send David Pastrnak a message. The slumping 21-year-old right wing was dropped to the third line in Boston’s 5-2 win over the Calgary Flames at TD Garden as big, physical David Backes took Pastrnak's spot alongside Patrice Bergeron and Brad Marchand on the Bruins' top line.

Pastrnak finished with a minus-1 rating and a couple of shots on net in the win, and acknowledged that he had some work to do.

“I don’t mind playing with anyone, you know?" he said. "I think I’m the kind of player, you know, I can find chemistry with someone. I don’t know. I want to be better, and we’ll see. I was trying to get better. I need to kind of get better and think what I will do, and what will be the best for the team.”

Some of it was clearly about the matchup against a gritty, fast-skating and skilled Calgary crew that doesn’t shy away from the contact. Cassidy admitted as much after the game.