The team said Staal underwent an MRI on his right knee Saturday and it revealed a third-degree sprain of his medial collateral ligament.
The team says Staal won't need surgery and he should need only three months of rehab.
Staal's injury Thursday during the world hockey quarterfinals in Stockholm certainly could have been a lot worse.
The captain of Canada's team collapsed to the ice in obvious pain following a knee-to-knee collision with Sweden's Alex Edler.
The durable Staal, 28, has missed only 14 games during nine NHL seasons. He led the Hurricanes with 35 assists and 53 points.