Thornton appeared to suffer a left knee injury in Sunday's game against Vancouver, and he was putting no weight on his left leg as he went to the locker room, Kevin Kurz of CSN Bay Area reports.

EDGE Analysis

This is awful news for Thornton, who's already seen a significant decline in production this year; he has just 50 points in 78 games, a huge drop from last season's 82 points. The injury looked bad, so fantasy owners should be preparing to be without Thornton for the duration of the season, and the Sharks should be thinking about what they're going to do at center; Patrick Marleau, Tomas Hertl and Chris Tierney will likely all be looking at increased minutes. We'll keep an eye out for a postgame update on Thornton's status.