Toronto captain John Tavares will probably miss the rest of the first-round series against the Montreal Canadiens after sustaining a concussion and a knee injury during Game 1. The center’s availability for the rest of the postseason is uncertain, if the Maple Leafs advance. General manager Kyle Dubas said there is no structural damage to the head, neck and spine after Tavares took an accidental knee to the face from Canadiens forward Corey Perry. Speaking by conference call before Game 2 on Saturday night, Dubas indicated the knee issue is expected to keep Tavares out of the lineup at least two weeks. The best-of-7 series would end May 31 if it went the distance. “The head injury and concussion, I think it’s very difficult to place a timeline on when someone’s going to return,” Dubas said. “We handle those in a very conservative nature, and handle them very sensitively.” Tavares …