The Sharks made the move Sunday. Thornton will miss at least the next two games in Winnipeg and Minnesota the next two nights.
Thornton had his streak of 319 consecutive games played snapped when he sat out Saturday against St. Louis. The Sharks lost the game 7-2. That was his first game missed since Nov. 11, 2010, when he served the second game of a suspension for an illegal hit.
Thornton was injured on a hit by Anaheim defenseman Clayton Stoner.
Thornton has nine goals and 24 assists and is tied for the team lead with 33 points this season.
San Jose also reassigned forward Micheal Haley to Worcester of the AHL.