BOSTON (CBS) — For the first time since defenseman Zdeno Chara agreed to join the Bruins as a free agent in the summer of 2006, the Bruins had to learn how to live without their captain this season.

They survived.

The Bruins were 11-7-1 while Chara was out recovering from a tear in his knee. A weak scheduled helped their cause, but the Bruins were also without Torey Krug, Kevan Miller and Adam McQuaid on defense and center David Krejci at different points of Chara’s absence. So they fared pretty well considering the amount of injuries they dealt with.

Their 9-8-5 record with Chara in the lineup tells you how much of a struggle this season has been for the Bruins. They traded Johnny Boychuk in a deal that made their defense corps weaker and younger. And Bruins defensemen young and old have produced to varying levels of satisfaction.

Here’s a look at the midseason grades for the Bruins’ defensemen:

Dougie Hamilton

Grade: B+

As one would expect from any 21-year-old defensemen, Hamilton has his shaky moments. He’s still getting a feel for when to go on the attack in the NHL, and he’s still getting stronger. Hamilton handled extra ice time in Chara’s absence pretty well and he’s continued to play more. His 23 points are the best among Bruins’ blueliners.

Zdeno Chara

Grade: C+

Even before his injury, Chara was struggling to keep up with some of the best opponents he was facing. He might’ve just been hitting his stride when he got hurt. But right now coach Claude Julien can’t lean on the 37-year-old for major minutes against the other teams’ top forwards. In fact, Chara’s overall ice time average is down two minutes from last season. That’s troublesome. Chara also hasn’t been able to score at the same clip as last season, even from his position in front of the opposing net on the power play. Chara has taken too many unnecessary penalties. Maybe the rust of his injury absence will fall of during the second half of the season.

Matt Bartkowski

Grade: F

He’s played in just 20 games, but that shouldn’t be an excuse at this point. The fifth-year pro’s maturation into a top-four defenseman has been stalled since late last season. While he’s still strong when we skates the puck up the ice, his decision making after he gets up ice or when skating the puck up isn’t an option, just never gets better. He moves forward when he should stay back, he stays back when he should go forward. And he still loses too many battles in the crucial areas.

Dennis Seidenberg

Grade: D

Extra consideration has been granted the 33-year-old because he came back this season after missing all but 34 games last season because of an ACL/MCL injury. But at some point this season the Bruins need Seidenberg to play like a defensive force that can be trusted in shut-down situations. So far he’s been far from that type of player this season. When Chara was out, Seidenberg was exposed. His decision making has suffered along with his mobility and the $4 million Boston is paying him is suddenly looking like a hindrance to their ability to build a championship team. It’ll be interesting to see if he raises his game with an improvement from the whole team or if Seidenberg is on the back nine.

Torey Krug

Grade: B+

The contract dispute that kept him out of training camp until late clearly had an impact on Krug. And then he had his finger busted by a slash. Neither occurrence did much to help Krug, but he still found a way to get his points and he’s improved his all-around play the past couple weeks as his finger has either gotten healthier or he’s just adjusted to it. Krug is one of the rare Bruins players that’s a threat to score every time he’s on the ice and he has 17 points (eight goals) in 37 games. He’s also better in his own end, as long as the Bruins don’t ask him to match up too far outside of his weight class.

Adam McQuaid

Grade: B-

If it’s a Bruins season, there must be a McQuaid injury. McQuaid missed 18 games with an injury. It’s always hard to grade a stay-at-home defenseman, but McQuaid generally doesn’t hurt the Bruins too much when cast in a third-pair role. Unfortunately the Boychuk trade forced McQuaid up the depth chart, and along with his veteran colleagues on the back end he’s has more rough outings than positive ones.

Kevan Miller

Grade: C+

Like McQuaid, it’s difficult to measure Miller’s contributions, especially when the injuries hit and he was asked to play a bigger role. Miller can be a physical presence and his willingness to defend his teammates helps out. But too often he gets beat in his own end. And his offensive game, while improved, still doesn’t contribute enough to make up for his defensive deficiencies.

Zach Trotman

Grade: B-

Currently back playing with Providence of the American Hockey League, Trotman showed some promise as a defenseman that could move the puck. He needed to be better at rebounding from mistakes, and some of that will be helped when he earns more confidence from the coaching staff. His NHL experience should pay off next season when he’s on a one-way contract and should be part of Boston’s sextet.

Joe Morrow

Grade: B

Go figure. Morrow was known for his high-risk play and questionable decision making in the AHL. He got the NHL and became a poised, solid defenseman. Of course he didn’t produce as much offensively as he would have liked, but he was a huge reason the Bruins survived their rash of injuries. You could argue he should still be in the NHL, but the Bruins have him back down on the farm. Later this season or next year, though, the Bruins should have a more than serviceable top-four defenseman when they give Morrow a full-time chance.

Matt Kalman covers the Bruins for CBSBoston.com and also contributes to NHL.com and several other media outlets. Follow him on Twitter @TheBruinsBlog.

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