The 19-year-old defenseman played for Finland at the past two tournaments. In five games at the 2018 WJC, he had one assist and a plus-3 rating averaging 16:36 of ice time.

Vaakanainen, selected in the first round (No. 18) by Boston in the 2017 NHL Draft, has two shots on goal in two games with the Bruins this season. He practiced Friday but has not played since Oct. 23 because of a concussion. He was placed on injured reserve Oct. 30.

"He's now cleared for contact, gone through a couple contact practices. So I assume the next stage is, OK, where do we get him playing," Bruins coach Bruce Cassidy said Friday before the move was announced. "Is that World Juniors? Is that for the Boston Bruins? Providence Bruins? … It's been a while. So we don't want to push him into a game when he's not prepared."

The 2019 WJC starts Wednesday and runs through Jan. 5, in Vancouver and Victoria, British Columbia. Finland is in Group B for the preliminary round and plays Sweden in its first game, at Save-On-Foods Memorial Centre in Victoria on Wednesday (10:30 p.m. ET; NHLN, TSN). Also in Group B are Kazakhstan, Slovakia and the United States.