Vaakanainen made his debut with Boston this season on November 12 and remained with the team for five games, earning a plus-two rating and recording two shots in that time.
The 21-year-old defenseman has four goals and eight assists through 42 games played this season with the Providence Bruins and ranks third on the team with a plus-14 rating. The 6-foot-1, 185-pound Finland native has played in seven career NHL games, including two in Boston during the 2018-19 season.