Will Dennis Seidenberg's injury be a blessing in disguise for Bruins? (Trending Topics)

In retrospect, re-signing Dennis Seidenberg was not a good decision. That's not to say it was even a good idea at the time, because it wasn't. But in retrospect it's really not good at all.

The team effectively chose Seidenberg — 33-year-old Seidenberg — over Johnny Boychuk, signing the big German for four years and $4 million just ahead of the 2013-14 season, for a deal starting in 2014-15. Around the same time, Boychuk was not yet entering the final year of his contract, and the Bruins, clearly worried about losing Seidenberg to free agency, went all the way to Oct. 4 before making the decision to trade Boychuk. Who is three years younger, and was even at the time demonstrably better.

Now, to some extent maybe you argue that the Islanders' decision to extend Boychuk for seven years at $6 million per was what Boychuk was going to be asking for to begin with, and that's a price the cap-strapped Bruins were never going to be able to pay starting this season, so cutting bait was necessary. But still, Seidenberg? In his age 33-through-36 seasons? Peter Chiarelli really ought to have been smarter than this.

It's well-established at this point that these are the twilight years of nearly every non-elite defenseman in the league. Very few successfully make it to even 35 and still have tread on the tires. And he's signed for a year beyond that at $4 million. That's Jake Muzzin money!

It's not just that defensemen lose the legs, either. Many, and especially the more physical ones like Seidenberg, end up seeing the injuries pile higher and higher. In 2013-14, not long after he signed that new deal, he played just 34 games due to a bum ACL. But hey, it's not like you need one of those to be in good working order if you want to be a competitive defenseman in the National Hockey League. Just kidding, guys. You actually do.

Now, to be fair to Chiarelli, Seidenberg's lockout-shortened season was his best one in a while, so that plus the looming cost of Boychuk was probably enough to convince him that the wheels weren't going to come off any time soon. But then there was the ACL injury the next season, and he wasn't even all that good when he was healthy and playing. Last season was obviously a disaster, and just about everyone in Boston realized that the wheels had probably fallen off, as they tend to do for 33-year-old rugged defensemen in this league.

Not that you need stats to tell you Seidenberg was poor last season, because watching just about any Bruins game would have given a prudent observer plenty of evidence in this regard, but the fact remains. Here is a look at Seidenberg's performances for Boston over the five full seasons he played there (i.e. not counting the end of 2009-10 when he was traded from Florida and played the final 17 games in Black and Gold:

What's interesting, though, is that most of the negative numbers you're seeing here come as a result of the rate at which he concedes shots, which has been quite high for a while now. It bears repeating that the above numbers are in comparison with what a replacement player (i.e. an AHL call-up) should be able to produce in his stead. So, for the number of wins he's been costing Boston for years now — his total WAR for his time in Boston is minus-2.42, and also keep in mind that the minus-0.98 was in just 34 games, which is incredible — to come solely from how badly he bleeds attempts in his own zone is pretty amazing.

It, in fact, speaks a lot to the thing the Bruins ended up talking about after last season: They couldn't get the puck out of their own zone with any kind of speed. Say, did they play any slow defensemen heavy minutes the last two years? Maybe some German ones? What's that, they did? Weird.

Indeed, Seidenberg's corsi-against per 60 since he came to Boston is 55.7, compared with the team's average of 51.3. Over the same period, Zdeno Chara — who is, granted, an elite defenseman — is just 50.7, which gives you an idea of the gulf between them, and they were supposed to have been the team's Nos. 1 and 2 defensemen, even if they played on different pairings. Indeed, it should come as little surprise to any observer that Seidenberg wasn't exactly drawing tough assignments in terms of personnel (fourth on the Bruins over this period), but that he was being deployed in a largely defense-only role.

This is every Boston defenseman of the last five seasons to play at least 2,000 total minutes. You can see Seidenberg wasn't exactly being put in a position to succeed, as far as zone-starts are concerned. (Also: Half of these guys aren't with the team any more, but two of the four they kept were somehow Seidenberg and McQuaid?)

That is, of course, going to hurt your shots-against numbers, and it's further interesting that the Bruins still did get the puck out of their own zone convincingly enough when Seidenberg was on the ice; at least on occasion. Further, despite the assignments, he did a pretty good job of not-taking penalties, which isn't easy to do when you're chasing the play.

All of this is a long way of saying that the team losing Seidenberg for as many as eight weeks, following his back surgery yesterday, might not be the worst thing in the world. Back problems can be nagging, so it might be fair to say they could have greatly hampered his performance last season. Perhaps two months from now, Seidenberg is a new man with the ability to really turn his career around. But, y'know, probably not.

That does create a (possibly desirable) hole in the Bruins' lineup, though, and it's one that probably gets filled by committee. They of course have Torey Krug, the little guy in the bottom right of the above chart, who pummels bad competition for quality points. Claude Julien has expressed a desire to cast Krug in a role where he doesn't have to be used in such a, shall we say, specialized manner, and this seems the perfect opportunity to at least test the waters there.

People have bemoaned Boston's blue line — and no, it sure isn't great if Seidenberg is your No. 2 — but they do have some decent depth players that may be able to get things done. Newly signed Matt Irwin is something of an unknown quantity but his time with the Sharks showed he could be effective in the middle of the lineup for a good possession team. Zach Trotman looks like he's going to be Chara's regular partner, which tells you a lot, but he at least appears to be pretty good. The Bruins also have a pair of rookies in Colin Miller, who excelled at the AHL level in the Kings organization last year, and Joe Morrow, who seems ready to be an NHLer as well.

Now, that's not to say those guys will succeed there — and one thing Julien 100 percent shouldn't do is try to get Adam McQuaid and Kevan Miller to fill those gaps — but the fact is that they probably won't hurt the team as badly on a per-game basis as Seidenberg has if he's out until late November or early December.

(And given the developments last night, it's uncertain whether Zdeno Chara is even going to be healthy to start the season, in which case you're in full-on disaster mode to begin with. That would leave the Bruins with precisely zero proven top-four defensemen. But even if he is, it would also be unwise to mix more minutes for billion-year-old Zdeno Chara, but that's something the Bruins might try as well.)

If we're talking eight weeks to the day (Sept. 24), Seidenberg will miss 20 games, which is obviously a big chunk of the season, but as long as the combined efforts of these good, younger guys don't cost the team half a win, which I think is a feat that would be tough to match even collectively, it won't be enough to match the harm Seidenberg inflicts on his team.

Of course, Don Sweeney could just go out and make a trade for someone to fill that middle-of-the-lineup role today, and that wouldn't be a surprise either. It would probably be imprudent to do so, given how many NHL defensemen are ready to be on the roster already (eight including Seidenberg, so seven currently), but this is Don Sweeney we're talking about, so anything is possible. And again, if Chara's hurt, that's probably something he has to do just so the Bruins don't have to dress forwards as defensemen or something. But again, if Chara is out for even a stretch of six or seven games, the Bruins have much bigger problems than who replaces Seidenberg.

If nothing else, this two months should be a healthy period for the Bruins to evaluate what life would be like without Seidenberg. If things go well — and that's not a guarantee — it could be enough for them to see if they can unload him on any team dumb enough to take that contract.

But things not-going well probably wouldn't be the fault of the defensemen used to fill the Seidenberg-shaped hole in the lineup. Using a player with such negative on-ice value, and at such a high price point, is a different problem entirely, and well above their pay grade.

Ryan Lambert is a Puck Daddy columnist. His email is here and his Twitter is here.

All stats via War on Ice unless otherwise stated.

MORE FROM YAHOO HOCKEY: