Subban is expected to join the team Tuesday. Canada will play a quarter-final game Thursday in Stockholm.
He became available after the Canadiens were eliminated in the first round of NHL playoffs by the Ottawa Senators.
Subban hasn't played in a world championship before, but won gold medals with Canada at the world junior championship in 2008 and 2009.
Subban is a finalist for this season's Norris Trophy, which goes to the top defenceman in the NHL.
Canada now has three goalies, 12 forwards and nine defencemen for 24 players. Countries can carry a maximum of 25 players.