Every NHL season has its share of surprises (good and bad), and 2011-12 was no different. Here’s the notable ones of this season which caught my eye.

St. Louis Blues tops in the standings. For the past couple of years, the Blues were considered a promising, but underachieving, young team. Since they hired Ken Hitchcock as head coach in early November, the Blues steadily improved to where they’re among the league’s elite this season. Yes, they do have some offensive issues, and an average road record, but with their strong goaltending and defense, they should be a tough opponent in the upcoming playoffs.

Boston Bruins stumbling down the stretch. The defending Stanley Cup champions got off to a slow start this season, then went on a nearly two-month stretch where they were practically unbeatable, seemingly poised to run away with first overall in the East. Since early-February, however, the Bruins have been sputtering, due to a combination of injuries to key players and inconsistent play. Two months ago, the Bruins appeared the team to beat in this year’s playoffs, perhaps the first team to repeat as Cup champions since the late-1990s. Now, unless they turn things around soon, they could be in danger of falling out of the playoffs.

Ottawa Senators challenging for the Northeast Division title. Only die-hard Senators fans expected this team, in the midst of a significant rebuild, to even qualify for the playoffs, let alone challenge for the divisional lead. After a roller coaster first half, the Senators have been among the hottest teams in the league since early February, challenging the Bruins for first in the Northeast, and could finish this season as a top seed in the Eastern Conference.

Karlsson as a Norris contender among this season's surprises.

Erik Karlsson, Norris contender. Everyone knew Karlsson was going to be good, but no one expected the 21-year-old Senators defenseman to break out the way he has in this, his third NHL season. Karlsson is not only running away with the scoring lead among defensemen, he’s the only blueliner in the top ten in the league points race. He’s smashed the team records for assists and points for defensemen, and while his defensive game still needs work, Karlsson has made considerable improvement in that area. Little wonder Karlsson is expected to be among the top nominees for the Norris Trophy as the league’s best defenseman.

The San Jose Sharks and Washington Capitals struggling to make the playoffs. The Anaheim Ducks, LA Kings, Buffalo Sabres, Montreal Canadiens, and Tampa Bay Lighting have surprised with their poor performances this season. Seeing the Sharks (perennial Pacific Division leaders and two-time Conference Finalists) and Capitals (four-time Southeast Division leaders, two-time Conference regular season leaders) battling for their playoff lives is the biggest surprise of the bunch. For the first time, pundits and fans are wondering if the Sharks window of opportunity to contend for the Stanley Cup is closing, while puzzling over the reasons for the Capitals stunning struggles this season.

Brian Elliott leading the league in save percentage and goals-against average. Following last season, it appear Elliott’s NHL career might be in jeopardy. Having been dealt by the Senators to the Avalanche late last season, then cut loose by the Avs last summer, Elliott was signed by the St. Louis Blues as a backup for Jaroslav Halak. When Halak struggled in the first half, Elliott’s stepped in with a solid effort which earned him a berth in the All-Star Game, and a  two-year contract extension. Halak has earned most of the starts in the second half as his performance has improved, but Elliott has saved his NHL career, pushing Halak in the process to improve his play.

Jordan Eberle’s sophomore season. Nearly lost amid another disappointing season for the Oilers and the star power of sophomore left wing Taylor Hall and rookie star Ryan Nugent-Hopkins has been Eberle’s performance this season. He showed a lot of promise as a rookie last season, with 43 points in 69 games, but this season is on pace to nearly double that points total, and with only 8 PIMs this season, should be considered a Lady Byng trophy candidate. It’s not that Eberle isn’t a talented player which is surprising, but rather how quickly he’s emerging as a star in his own right. Only 21, Eberle is emerging as the leader of the Oilers young stars.

Penguins overcoming injuries to rank among league leaders in points. The Pittsburgh Penguins entered this season expected to be among the best teams in the league, but they’ve been hit by injuries to a number of key players, leading the league in man-games lost to injury this season. Among the notable who’ve been sidelined: Sidney Crosby, Evgeni Malkin, Jordan Staal, Kris Letang, Tyler Kennedy, Paul Martin and Zbynek Michalek. Losing players like that would usually be potentially fatal to a club’s playoff chances, yet thanks to their depth and the coaching of Dan Bylsma, the Penguins have overcome adversity to remain among the league’s elite. By mid-March, they were finally healthy (only backup Brent Johnson remains sidelined) and with all their best players now back in the lineup together, the Penguins could  become the team to beat in the Eastern Conference.

Corey Crawford’s sophomore slump. The biggest concern for every player following a promising rookie season is how to avoid the dreaded “sophomore slump”. This is especially true for young goalies tagged with being their team’s full time starter. Crawford played very well last season as the Blackhawks starter, coming within an overtime period of carrying his club past the eventual Western Conference champion Vancouver Canucks in the first round of the 2011 playoffs. Expectations were high for Crawford this season, but he’s struggled to meet them. After going 33-18-6 with a 2.30 GAA, .917 SP and 4 shutouts, Crawford’s record this season is 24-16-5, with a 2.85 GAA, .902 SP and no shutouts. Since late-February, Crawford’s lost playing time to backup Ray Emery and has been at a loss to understand the decline in his play.

What happened to Drew Doughty? Two years ago, Doughty was a key player for Canada’s gold medal-winning Men’s Hockey Team at the 2010 Winter Olympics, was nominated for the Norris Trophy and seemed poised to become the NHL’s dominant defenseman. A concussion last season adversely affected his numbers, but it was expected he’d bounce back in 2011-12. A protracted contract dispute with Kings management, however, resulted in Doughty missing training camp, and when he returned, it took weeks to return to full game shape. Only 22, Doughty has yet to reach his prime, and better seasons are likely ahead, but his much-anticipated breakout failed to materialize this season.

What surprised you during this NHL season? Drop a line in the comments and let me know!