The 2004–05 NHL season was the National Hockey League's 88th season of operation. The entire 1,230-game schedule (that was supposed to begin in October) was officially canceled on February 16, 2005 due to an unresolved lockout that began on September 16, 2004.
The loss of the 2004–05 season's games made the NHL the first North America professional sports league to lose an entire season of games because of a labor dispute.
It was the first time since 1919 when a Spanish flu pandemic canceled the playoffs, that the Stanley Cup was not awarded.
This canceled season was later acknowledged with the words "2004–05 Season Not Played" engraved on the Cup.
According to the International Ice Hockey Federation, 388 NHL players were on teams overseas at some point during the season, spread across 19 European leagues.
Many of these players had a contract clause to return to the NHL when the league started up again, even if it was during the current season.
Key rule changes which would dominate after the lockout were established as a result of a meeting between the NHL and its top minor league, the American Hockey League.
On July 5, 2004, the AHL announced publicly the 2004–05 rule changes, many of which were passed as a result of the NHL's recommendation for experimentation.
At the American Hockey League Board of Governors meeting in June of 2004 at Hilton Head Island, South Carolina, the Board, in agreement with the NHL, agreed to adopt new rules for the season.
- In case of a tie game after overtime of regular season games, there is a shootout with five shots per team, and if it is still tied, the shootout becomes sudden death. The shootout would be similar to what is used in most minor leagues which have adopted the rule, such as the ECHL.
When the NHL resumed play, shootouts were cut to an initial three shots per team.
- The "tag-up offside" rule that was eliminated in 1996 was reinstated for 2004-05. An attacking player is considered offside if he enters his offensive zone prior to the puck entering the zone.
- Between 1996 and 2004, if a player was offside, the play would continue only if the attacking players cleared the zone and allowed the defending team to carry the puck all of the way out of the zone.
- The tag-up offside rule allows for play to continue as long as all offside players are clear of the offensive zone simultaneously by touching the blue line (and "tag up") prior to touching the puck or becoming involved in the play.
- Goaltenders' leg pads were reduced in size from 12" (30 cm) to 11" (27.5 cm). This rule was postponed for a season, but by the resumption of the NHL, the leg pad rules were in effect. However, the original proposal was to cut the pads down to 10" (25 cm).
- Automatic ("no-touch") icing, as enforced in other minor leagues such as the ECHL, was enforced. An icing infraction is called immediately when the puck crosses the goal line. This rule did not continue into the next season of the AHL or NHL.
- Blue and red lines were doubled in width, from 12 inches (31 cm) to 24 inches (62 cm). This added additional space to the neutral zone in between the blue lines. Passes would still be allowed from the defensive edge of the blue line to the offensive edge of the red line.
- Goal lines were moved two feet closer to the end boards, from 13 feet to 11 feet. The blue lines were moved to maintain a 60-foot neutral zone in a 200-foot rink.
- During the first seven weeks of the 2004-05 AHL season, an experimental rule added a new trapezoid-shaped zone directly behind the net, restricting the area where a goaltender may play the puck behind the net. This rule was approved permanently after the seven-week experimental period.
These rule changes combined to make games shorter by 10 to 15 minutes per game, therefore improving the quality of the game by having less downtime.
As a result of the lockout, no Stanley Cup champion was crowned for the first time since the flu pandemic in 1919.
This was controversial among many fans, who questioned whether the NHL had exclusive control over the Cup.
A website known as freestanley.com (which has since closed) was launched, asking fans to write to the Cup trustees and urge them to return to the original pre-NHL Challenge Cup format.
Adrienne Clarkson (the then Governor General of Canada) alternately proposed that the Cup be presented to the top women's hockey team in lieu of the NHL season, but this idea was so unpopular with NHL fans, players and officials that the Clarkson Cup was created instead.
Meanwhile, a group in Ontario (also known as the "Wednesday Nighters") filed an application with the Ontario Superior Court, claiming that the Cup trustees had overstepped their bounds in signing the 1947 agreement with the NHL and therefore must award the trophy to any team willing to play for the cup regardless of the lockout.
On February 7, 2006, a settlement was reached in which the trophy could be awarded to non-NHL teams in the event the league does not operate for a season, but the dispute lasted so long that.
By the time it was settled, the NHL had resumed operating for the 2005–06 season, and the Stanley Cup went unclaimed for the 2004–05 season.