In one of the most surprising developments in recent NHL playoff history, the star-studded Pittsburgh Penguins are one loss from being swept out of the Eastern Conference Final by the Boston Bruins, a team they had defeated six straight times before this series.
Judging by the first three games—which Boston won by a combined score of 11-2—it's now time to determine whether or not this Penguins team that's loaded with depth and talent is more vulnerable than we originally thought.
The Penguins appeared to be unstoppable in Round 2 when they clinically defeated the Ottawa Senators in five games, outscoring them 22-11. But the Senators aren't a team that's going to win a lot of high-scoring games. The Penguins could get away with turnovers and defensive mistakes against Ottawa because it wasn't a threat to score many goals throughout the series.
The first two games of the conference finals highlighted Pittsburgh's weaknesses in its own end, most notably a lack of size, defensive skill and mobility.
The Penguins finished the regular season ranked 12th in goals-against average and played well defensively in the second round, but they have looked terrible at times in their own zone against the Bruins. They don't have a true shut-down, No. 1 defenseman like a Zdeno Chara, Drew Doughty or Duncan Keith who will log 25-plus minutes per game and excel defensively. This is a major concern against four-line teams like the Bruins.
Norris Trophy finalist Kris Letang is not a great defensive player, but few people would have expected him to struggle so much in his own zone over the first three games. He has a minus-five rating and an unusually high amount of turnovers, many of which resulted in good scoring chances for Boston.
There were several instances in the Bruins' 6-1 victory in Game 2 where Letang looked lost in his own zone, including Nathan Horton and Patrice Bergeron's goals. Letang has not been able to handle the aggressive Bruins forecheck and their overall size, as he's undersized for a No. 1 defenseman who's asked to defend the opponent's best forwards for over 20 minutes each game.
When the Penguins won the Stanley Cup four years ago, they had defensemen such as Rob Scuderi, Brooks Orpik and Hal Gill to excel defensively in a shut-down role. It's almost impossible to hoist the Cup without these kinds of players, which is why the 2013 edition of the Penguins is not suited to win in the playoffs.
Pittsburgh's blue line has a lot more offensive skill than it does physical strength and defensive talent. The New York Islanders and Senators don't have the players to expose these weaknesses for 60 minutes, but the Bruins do because of their depth and size.
On offense, this series has been a complete disaster for Pittsburgh. This team led the NHL in goals per game and power-play goals through two rounds, but the team's top forwards, including Sidney Crosby, Evgeni Malkin, James Neal, Jarome Iginla and Brenden Morrow, are all scoreless through three games.
The Bruins are a great defensive team, but the ease with which they have outmuscled and won the majority of the 50-50 puck battles was unanticipated.
The Penguins' lack of strength and size in their top six has been a bigger problem than many predicted before the conference finals. This is largely because Pittsburgh overestimated the impact that Morrow and Iginla would have on the team's ability to play a physical game and score goals consistently.
Inserting these two veteran forwards into the lineup also made the Penguins a much slower team, which plays right into the Bruins' hands. Boston doesn't want to play a fast-paced game given its lack of speed on the back end.
From a mental toughness standpoint, it was surprising to see how vulnerable this Penguins team was in Games 1 and 2, when the Bruins frustrated them with physical play, trash talk and after-the-whistle jabs.
This Pittsburgh team is full of veteran players with championship experience. They acquired two captains in Brenden Morrow and Jarome Iginla at the trade deadline, but Boston was still able to rattle them and cause them to lose focus.
The Penguins actually out-hit the Bruins in the first two games, which helps show that they didn't have as much puck possession as expected. They were too caught up in the emotions of the game, and there was a troubling lack of leadership from Crosby and the other veterans.
We saw the Penguins lose their composure in last year's playoff versus the Philadelphia Flyers, but it was expected that the veteran experience the team added before the trade deadline would prevent this situation from happening again. When teams lose their cool, it's so much easier to beat them, and this is what happened in Pittsburgh to start the series.
But it would be unfair to deny the Bruins a proper amount of credit for the way they have performed in this series. Boston head coach Claude Julien's rigid defensive system and his top players, highlighted by the first line of Nathan Horton, Milan Lucic and David Krejci, have exposed Pittsburgh's flaws better than any team this season.
The Penguins have proven to be a more vulnerable team than many would have expected prior to the playoffs, which will give GM Ray Shero many tough roster decisions to make in the summer with 10 players whose contracts are set to expire at season's end.
Nicholas Goss is an NHL Lead Writer at Bleacher Report. Nick was a credentialed reporter at the 2011 Stanley Cup Final and 2012 NHL playoffs. He is also a credentialed writer at the 2013 NHL playoffs. Contract information via Capgeek.