BOSTON -- Boston Bruins captain Zdeno Chara will miss four to six weeks with torn ligament in his left knee.

Bruins general manager Peter Chiarelli says surgery isn't likely an option right now.

Chara tore the posterior cruciate ligament in a collision with Islanders captain John Tavares midway through the first period of Thursday's game. The star defenceman then played one more shift that ended with 8:04 remaining in the period. There was no outward indication of an injury at that time.

It's a big loss for the Bruins, who play the Maple Leafs in Toronto on Saturday night.

The six-foot-nine Slovakian, a third-round pick of the Islanders in 1996, is Boston's No. 1 defenceman and spends more time on the ice than any other Bruins player. He has two goals and an assist in nine games this season.