The Carolina Hurricanes' bubble has been popped. 

For the second straight year, the Hurricanes met the Boston Bruins and had their playoff hopes squashed rather quickly. Last year, it happened with a sweep in the Eastern Conference Final. This year? It took five games in the first round. 

Carolina looked great as they swept the Rangers in their best-of-five qualifying round series, so where did things go wrong against a Bruins team that looked extremely rough in the round robin stage? Let's take a look at some of the reasons why the Hurricanes are heading home. 

Special teams

This is probably the easiest place to start. Carolina is typically a strong possession team at five-on-five but they spent too much of this series on the penalty kill. They were undisciplined and didn't get much help from some questionable officiating, and it came back to the haunt them in the form of a Bruins power play that had the second-best conversion rate during the regular season.

Over the course of the five games in this series, the Hurricanes went shorthanded 19 times and surrendered five power play goals to Boston -- including the Bruins' only two goals in the series-clinching Game 5. 

Meanwhile, Carolina's own power play failed to mitigate the deficiencies of their PK. They went just 2-for-15 (13.3 percent) on the man-advantage and, woof, did they ever look rough at points. In just under 28 minutes of power play time in the series, the Hurricanes registered just 23 shots on net. 

And half of their power play goals in the series looked like this:

The Svechnikov injury

Yes, the Bruins were without David Pastrnak for three of the five games in this series, so maybe it's a little tougher to point to the Andrei Svechnikov injury as a reason why the Hurricanes are leaving the bubble so early. But his absence certainly didn't help, that's for sure. 

Svechnikov missed the final two games of the series after suffering an apparent lower-body injury when he got tied up with Zdeno Chara and fell awkwardly in front of the net during Game 3. It was a brutal blow for the Canes, who rely on Svechnikov's contributions as part of a fearsome top line that also features Sebastian Aho and Teuvo Teravainen. The 20-year-old Svechnikov had seven points in six games (two in three games vs. Boston) this postseason and his ability to generate offensive opportunities makes him one of the Canes' best forwards. 

It's hard to blame a single absence for why a pretty deep Carolina team got eliminated (especially when the Bruins were without their top goal scorer and starting goaltender for a majority of the series)  but if there were a list of players that the Canes couldn't afford to lose, Svechnikov's name would be almost near the top. They needed the first line to be at top form and Svechnikov's injury essentially guaranteed that wouldn't be possible. Which brings us to the next point...

Failure to outperform Bruins' top six

With both teams missing a key member of their top line for a portion of the series, the edge still went to Boston. 

Sebastian Aho and Teuvo Teravainen had solid series, leading the Canes in points with four and three, respectively, but they needed to do more to neutralize the efforts of their top competition -- Patrice Bergeron and Brad Marchand -- on the other side. Losing Svechnikov hurt the Canes' top line, which was utterly dominant against the Rangers, and that top unit only had a relatively modest net impact on the series. Even though the Hurricanes outscored Boston 3-2 while Aho was on the ice at five-on-five, their best forward and leading scorer failed to score a single goal in the series. 

But even without Pastrnak available for three games, Bergeron and Marchand were able to showcase why they're considered elite two-way players. Both finished as point-per-game producers, with Marchand recording seven points and Bergeron picking up five. That duo played over 60 minutes together at five-on-five and were on the ice for three Bruins goals, zero goals against. They controlled 68 percent of shots on net. 

It's a nearly impossible task to completely shut down the Bruins' top line with or without Pastrnak but the Hurricanes' top unit simply wasn't spectacular enough to take control of the series and dictate play. Throw in the fact that the Bruins' second line -- led by David Krejci, who may have been the series' best skater -- was far better than its counterpart and, well, it's not surprising that this thing ended so quick.

That collapse in Game 4

I mean, we all felt it, right? As the final buzzer sounded in Game 4, it truly felt like the series was over right then and there. It wasn't simply because the Bruins had beaten the Canes to go up 3-1 in the series -- we've seen teams dig themselves out of deeper holes, including against Boston -- but it was because of how the Bruins beat the Canes. 

Carolina carried a 2-0 lead into the third period of Game 4 and had Boston totally frustrated. The Bruins couldn't buy a goal (or a save from Jaroslav Halak) and it looked like the series was destined to be evened at two games apiece. But then the third period...oh boy, that third period. 

The Bruins came out of second intermission, caught the Canes flat-footed and absolutely steamrolled them for nearly 20 full minutes. The result? Boston controlled 75 percent of all attempts in the third period, out shot Carolina 16-2 and outscored them 4-1 -- including four straight devastating daggers on the scoreboard. It felt like Boston was fully imposing its will and they were intent on straight-up breaking Carolina physically and mentally. 

Even for someone like myself, who fully bought-in on the Canes and picked them to win the Eastern Conference, the Carolina collapse to close out Game 4 seemed like the end. That seemed nearly impossible to recover from, especially with the Canes pushed to the brink of elimination.

Bruins started playing like it mattered

On paper, this series featured a No. 4 seed (Boston) vs. a No. 5 seed (Carolina). In reality, though, it was this season's Presidents' Trophy winners versus a Wild Card qualifier. I picked Carolina to win the series in seven games because I really liked their roster (especially the top line and defensive corps) and they looked incredibly dialed in during the play-in round. Meanwhile, the Bruins looked absolutely terrible during the round robin.

But I acknowledged that if both teams played their best hockey, the Bruins would likely win. They didn't seem to take the round robin stage seriously and I questioned whether they could snap out of their "meaningless games" mentality to jump right into playoff hockey against a good opponent. They managed to do just that.

Unfortunately for the Hurricanes, it proved to be an unfortunate (and probably undeserved) first-round draw against the league's top team during the regular season -- a much different experience than the one the Rangers provided.