If I’ve said it once I’ve said it a thousand times: in order for the Boston Bruins to make a legitimate run at the Stanley Cup, they must add depth to their blue-line.

It’s been proven time-and-time again; when the blue-line starts dropping — especially in the playoffs — finding last minute replacements can be tough when those potential needs aren’t addressed by the seasons’ trade deadline.

Back in 2008-09 playoffs, both Matt Hunwick and Andrew Ference were limited to just four total games after their respective illnesses and injuries. Their voids caused D-men such as Steve Montador and Shane Hnidy to step-up and log more minutes than usual.

Last year was very apparent also. The whole city collectively gasped when they found out that No. 2 defenseman Dennis Seidenberg was to miss the rest of the season and all of the playoffs. Mark Staurt’s injury bug had him sidelined for all but four post season appearances last year — posting zero points and a minus-4 rating. Both injuries saw Johnny Boychuk and Hunwick skate over 26 minutes per game, which was nearly nine more minutes that their regular season average.

Insert Adam McQuaid, the No. 7 call-up from AHL Providence. The 23-year-old, who all-things-considered played well in his first NHL playoff appearance,  played just north of 10 minutes per game in nine of the Bruins’ 13 playoff contests. But the “what if” question remains. What if there weren’t those injuries? Or, what if they had another veteran blue-liner for depth at D?

After dealing Dennis Wideman this offseason to the bring in some offensive power, the Bruins inked their remaining then-free-agent defensemen (Seidenberg, Boychuk, Stuart) to deals that would bring them back for at least the upcoming 2010-11 NHL season. There are a handful of young guns, including newcomer Nathan McIver, who will be waiting in Providence for their shot, but none with much — if any — NHL experience. Here are the probable starting six come October:

Chara: The captain posted just seven goals (lowest since 2002-03 with nine) and 47 points (lowest since 2006-07 with 43) last year. Big Zee has a great offseason workout regime but he will be turning 34 in March ’11. However No. 33 is the last of the concerns on the Bruins blue-line. The 6’9″ Chara  was one of many Bruins’ players to struggle offensively, but we can most definitely pencil him in again this year to log north of 25 minutes per game and continue his average of over a half-a-point per-game,

Seidenberg: Logs big minutes (on PP/PK), blocks a ton of shots, and is a very efficient puck mover out of the defensive zone, but Seidenberg has averaged 21 points and just 62 games per season over his last four. If the Germany native can continue pitch-in a bit more offensively (seven points in 17 games with Boston last year) in the No. 2 role, and stay on the ice for 75-plus games while playing No. 2 minutes, then the B’s top back-end core will be one of the league’s best.

Boychuk: The 26-year-old must repeat his performance of last season and emerge as a solid No. 2/3 defenseman on this team. If the 2008-09 AHL Eddie Shore winner (20-46-66, plus-19) can continue to progress as an offensive catalyst with that thunderous slapper on the blue-line, then the Bruins could have landed themselves a future No. 1 anchor.

Hunwick: Like all Bruins players last season, Hunwick’s numbers and production dipped tremendously from the 2008-09 season (6-21-27, plus-15 in 53 games) to his 2009-10 NHL Sophomore season campaign — including a handful of ‘healthy scratches’ via poor performances. The 25-year-old posted a measly 6-8-14, minus-16 and just 60 shots on goal. Playing in the final year of his two-year contract, Hunwick must turn it around and become that puck-moving defenseman, especially now that Wideman is gone.

Stuart: Up until last year, Stuart was the team’s leading Iron Man with 214 consecutive games played. And unfortunately for No. 45, between those three separate injuries, Stuart was playing some of his best hockey to date. Tough, rugged, and a good stay-at-home defenseman, the 26-year-old is going to have to use his slapshot more often and find a way to chip-in with some more offense this season.

Ference: With an average of 59 games played and under 14 points per season, the 31-year-old Ference probably isn’t expected to better his offensive game this year. With his recent contract raise and extension, and newest nickname among non-Ference supporters “Glass Groin”, has but a bullseye on the back of No. 21 this season. Unless Ference plays the No. 5/6 role while playing No. 5/6 minutes (16-18 TOI), the possibility of him getting banged-up and missing some games is very likely.

If any two of the aforementioned players were to go down with another case of the injury bug at the same time this season, for any period of time, defensemen in the pipeline such as Andrew Bondarchuk, Yuri Alexandrov, Jeff Penner, McQuaid and McIver would be called upon (Matt Kalman of TheBruinsBlog.net did an awesome job with his prospect rankings last month, with four of those defensemen in the top-10. I suggest you check them out).

What they lost:

Dennis Wideman: After a very poor display of hockey last season, Wideman was the scapegoat of the team and was booed out of town by even most of his supporters. But it’s easy to forget his 50-point campaign in 2008-09 when he finished with a plus-32 and had 9-22-31 scoring totals and a plus-26 by the All Star break in mid January.

Wideman had averaged over 78 games played and nearly 40 points per season over his last three seasons with the Bruins (256 games played, 33-86-119, plus-26, 514 shots on goal career totals in Boston), an average of nearly a half-point per game. In 30 career playoff games with the Bruins, Wideman tallied 1-21-22 totals with 65 shots on goal and a plus-4 rating — including a team-high last playoff season with 12 points (1 goal, 11 assists).

This isn’t to say that these AHLers guys don’t deserve their shot in the big leagues, because they most certainly do. And with players ultimately getting banged-up throughout the course of the grueling 82 game schedule, there’s a good chance we’ll see them in Boston sooner than later. But when you’re gunning for Lord Stanley’s Cup, relying on unproven prospects to fill the void during such a run just won’t cut it.