The NHL’s trade deadline passed at 3 p.m. yesterday, and before it did, a slew of trades had a very significant impact on the league’s balance of power. In all, 25 trades were consummated on “Deadline Day,” with 44 players and 28 draft picks moved, and it was interesting to see which GMs wheeled and dealt — and which of them stood pat.

Perhaps the most noteworthy trade came just prior to the deadline, when the Islanders shipped two highly touted forward prospects (Robert Nilson and Ryan O’Marra) and a 2007 firstround pick to the Edmonton Oilers in exchange for All-Star forward Ryan Smyth. The talented left wing had been with the Oilers for all of his 12 NHL seasons, and with 53 points in 53 games (including 31 goals) is on pace to establish career highs in numerous statistical categories.

There had been rampant speculation leading up to yesterday’s trade fest that the Isles might deal Jason Blake, an All-Star unrestricted free agent-to-be of their own whom they’ve had difficulty inking to a contract extension. But instead, the Isles emerged as surprise “buyers,” stepping up and paying a steep price to land Smyth. Judging by the moves made by their Eastern Conference competition, it was absolutely the right decision.

Currently one point behind the eighth-place Hurricanes with two games in hand (and two points behind the seventh-place Canadiens with three games in hand), the Isles have played increasingly well lately, trending upward at a crucial point in the season. Given the seemingly nonstop frustration and disappointment of the past 15 years, being a “now” team will be a refreshing change of pace for the Isles’ faithful.

In particular, it came as a huge surprise that Canadiens didn’t make a single upgrade. They’ve fallen precipitously in the standings over the past month and have lacked a bona fide second-line center all season long. Despite these obvious needs, the only deal the Habs actually made was to trade second-pair defenseman Craig Rivet to San Jose for promising young rearguard Josh Gorges and a first-round pick over the weekend.

And so, GM Bob Gainey pronounced his team to be “sellers,” leaving the locker room in severe disarray as a result, then failed to take advantage of an obvious seller’s market. The Habs’ failure to act could have an even bigger positive impact on the Islanders’ playoff chances than the acquisition of Smyth.

In one of yesterday’s biggest moves, the Sharks acquired power forward Bill Guerin from the St. Louis Blues in exchange for forward Ville Nieminen, prospect Jay Barriball, and a 2007 first-round pick. Guerin had enjoyed great chemistry playing alongside Sharks star Joe Thornton when they played for the Boston Bruins, and it’s likely the duo will team with Jonathan Cheechoo to form a dominant first line in San Jose.

The Detroit Red Wings also got into the action, sending two conditional draft picks to the Florida Panthers in exchange for burly power forward Todd Bertuzzi. Bertuzzi has missed all but seven games this season with a back injury but is expected to return to action relatively soon. If Bertuzzi is able to perform at a high level, he’ll more than replace the production lost when Brendan Shanahan left the Motor City to join the Rangers this season.

Of course, plenty of players who were rumored to be available didn’t end up going anywhere. And the most prominent player to fall into that category was Rangers superstar Jaromir Jagr. Though Jagr’s name reportedly came up in trade discussions, Blueshirts GM Glen Sather didn’t get an offer compelling enough to move the superstar forward, and instead made a few minor tweaks to his liminal lineup.

In one deal, Sather swapped defensemen with the Bruins, sending Aaron Ward to Boston in exchange for Paul Mara. Neither player has performed particularly well this season, and both seemed in dire need of a scenery change. In Mara, the Blueshirts have added yet another underachieving offensive defenseman, and it’s far more likely that he’ll go the way of Sandis Ozolinsh and Tom Poti than that he’ll emerge as the second coming of Brian Leetch. But the disappointing Ward had worn out his welcome on Broadway, and so this deal carries very little risk for Sather.

In another trade, the Rangers sent Pascal Dupuis to Atlanta in exchange for promising young forward Alex Bourret. The 16th overall pick in the 2005 Entry Draft, Bourret may well evolve into a topline forward for the Rangers. For Sather, whose team has a plethora of players similar to Dupuis, this was a very impressive return, and could well turn out to be one of the biggest steals of the day.

Not surprisingly, the Devils were relatively inactive, pulling off only one trade. They sent defenseman David Hale and a fifth-round pick to the Calgary Flames in exchange for a third-round pick, a deal that was far more about clearing salary space for the soon-to-return Richard Matvichuk than it was about a strategic exchange of assets. For while Hale might slot into the Flames’ lineup as a sixth defenseman, Matvichuk’s presence will significantly improve the Devils’ Cup chances.

The Pittsburgh Penguins, who have surged into fifth place in the Eastern Conference (a point behind fourth-place Ottawa with a game in hand), placed a strong priority on team toughness and veteran leadership in the hours preceding the deadline. They acquired hard-nosed forward Gary Roberts from the Florida Panthers in exchange for promising young blueliner Noah Welch, then sent prospect Danny Carcillo and a 2008 third-round pick to Phoenix in exchange for enforcer Georges Laraque. To make room for the two new forwards, the Pens shipped checking center Dominic Moore to Minnesota for a 2007 third-round pick; it’s a solid bet that the penalty-killing specialist will fit in well on Jacques Lemaire’s team.

Will the maneuvering pan out? For all but one team — the eventual Stanley Cup winner — the ultimate answer is “no.” But as the Oilers discovered last season when they acquired Dwayne Roloson for a first-round pick — a trade that earned them substantial ridicule at the time — the right trade can mean the difference between missing the playoffs and coming within one game of winning the Cup. Will Smyth make the difference for the Isles, Bertuzzi for the Wings, or Guerin for the Sharks? We’ll find out soon enough.

Mr. Greenstein is the editor in chief of InsideHockey.com.