The Canadian Hockey League has suspended Thrower for the rest of the tournament for his check to the head on Portland Winterhawks forward Taylor Leier.
Thrower hit Leier as he cut into the Blades' zone in the first period of Portland's 4-2 win on Wednesday night. A bloodied Leier lay motionless before being helped off the ice. There was no penalty called on the play.
"It's pretty obvious that it's a vicious hit to the head," Portland coach Travis Green told reporters Thursday. "It should have been a five-minute major."
Green said Leier has concussion-like symptoms and is "not doing that well."
"I'm not sure if we're going to see him again in the tournament or not," he said. "Doubtful that we will."
Leier, a 19-year-old fourth-round pick of the Philadelphia Flyers in 2012, had 27 goals and 35 assists in 64 games with Portland this season. The five-foot-11, 178-pound Saskatoon native has one goal and two assists at the Memorial Cup.
The six-foot, 197-pound Thrower was selected in the second round of last year's NHL draft by the Montreal Canadiens. The 19-year-old from North Vancouver, B.C., had six goals, 21 assists and 89 penalty minutes in 54 games for the Blades this season.
The Blades meet the London Knights in Thursday's tiebreaker game, with the winner moving on to face Portland in Friday's semifinal.