BOSTON -- Bruins defenseman Zdeno Chara suffered a tear to the posterior cruciate ligament in his left knee and will be sidelined for four to six weeks, general manager Peter Chiarelli said Friday. Chara will not need surgery.

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"Good news is it's isolated to that ligament. Bad news is he's out four to six weeks," Chiarelli said. "It might be a little bit earlier than four weeks, but a conservative time frame would be four to six weeks."

Chara suffered the injury during the first period of the Bruins' 3-2 loss to the New York Islanders on Thursday at TD Garden. He put a hit on the Islanders' John Tavares in front of the Bruins' net, but Chara showed no ill effects and finished his shift with 8:13 remaining in the first period. He exited the ice, went to the locker room and did not return.

"It's obviously a blow," Chiarelli said. "He's one of the premier defensemen in the league, but I'd rather have it four to six weeks than four to six months."

Since joining the Bruins in 2006, the Bruins are 341-204-66 with Chara in the lineup during the regular season, and 8-7-5 without him. Chara missed a five-game stretch with a shoulder injury during the 2007-08 season, which is the longest he's been out of the lineup during his tenure in Boston.

"You hope everyone else picks up the slack," Chiarelli said. "We've had a stretch before, might not have been four to six weeks, more like three weeks where Z was out. They don't happen too often, but you hope everyone picks up the slack and we play a solid defensive game."

Added Chiarelli, "You obviously want the other D to pick up the slack. You want to play a tighter defensive game. We're not going to have Z. ... He plays that shutdown, so we're going to need guys to play a better defensive game -- forwards and D. We have to play a tighter defensive game."

Bruins coach Claude Julien believes the team can succeed without it's best player.

"There's no discouragement in that room. There's no issues there at all, to be honest," Julien said. "It's more about it's opportunities for players, and if we become that bad of a team because of one player, it's not a real good sign for our hockey club. ... You've got to hope that your team is strong enough as a whole to overcome these things. Did we lose a good player? We did. Is he a big part of our team? Yes, he is. But I'd like to think we're better than that, than feeling sorry for ourselves, or be discouraged. That's not the case in our dressing room right now."

The Bruins have recalled defensemen Joe Morrow and Zach Trotman from Providence of the AHL.

"They're both strong kids. They're both good skaters. They both can find seams, can find lanes," Chiarelli said. "Joe's been a consistent performer down there this year. Zach just lately has been picking up his game. They're both strong kids that can skate."