Beaulieu was drafted 17th overall in the 2011 NHL Entry Draft. He played six games for Montreal last season, with two assists and a plus-5 rating.
He had been assigned to the Canadiens' minor-league team in Hamilton, but the Bulldogs have yet to play a game this season.
Pacioretty has been out with an injured wrist.
Gionta joined his teammates in Calgary on Tuesday after attending to a "family emergency."