Thrower, 20, had 39 points (12 goals, 27 assists) in 42 games this season with the Vancouver Giants of the Western Hockey League. His plus-9 rating led the Giants and his eight power-play goals led all Vancouver defensemen.
In 285 games since his junior debut with the Saskatoon Blades in 2009-10, Thrower has 147 points (42 goals, 105 assists), 414 penalty minutes and a plus-39 rating. He added five points (two goals, three assists) and 23 penalty minutes in 26 playoff games.
The native of Squamish, British Columbia, was the Canadiens' second-round pick (No. 51) in the 2012 NHL Draft.
Karlsson, 23, had 25 points (nine goals, 16 assists) and 14 penalty minutes in 48 games with Skelleftea AIK of the Swedish Hockey League in 2013-14. He was tied for seventh on the team in points, third in faceoff percentage (52.8 percent), tied for fifth in assists and eighth in goals to help lead Skelleftea AIK to the league's best regular-season record (111 points) for the second straight season. In 216 career SHL games, all with Skelleftea AIK, Karlsson has 66 points (31 goals, 35 assists) and 46 penalty minutes.
Karlsson also had 12 points (four goals, eight assists) in 14 playoff games as Skelleftea AIK won its second consecutive SHL Championship. The native of Lycksele, Sweden, has 32 points (nine goals, 23 assists) in 71 career playoff games.