Thornton was hurt on a shoulder-to-shoulder check by Raffi Torres in the third period of a 4-2 loss to Vancouver on Sunday that put the Sharks in a 3-1 series hole.
Thornton did not take part in an optional skate on Monday before the Sharks flew to Vancouver. McLellan says Thornton told him he was good to go for Tuesday's Game 5. Thornton leads the Sharks with 17 points this post-season.
Defenceman Jason Demers did practise for the first time this series and says it's up to the coaches whether he will play. Demers missed the first four games with an undisclosed injury.