The league's planned realignment from six divisions to four conferences for next season had been approved by the board of governors in December pending input from the NHL Players' Association.
But the league's plan was stalled Friday after the union opposed the changes. Instead, the NHL will maintain its current alignment and playoff format for the 2012-13 season.
"Players' questions about travel and concerns about the playoff format have not been sufficiently addressed. As such, we are not able to provide our consent to the proposal at this time," union head Donald Fehr said in a statement.
"We continue to be ready and willing to have further discussions should the league be willing to do so."
Fehr added the league had set a Friday deadline for the union to approve the plan.
Deputy commissioner Bill Daly said the league was unable to address the union's concerns despite four weeks of negotiations.
"It is unfortunate that the NHLPA has unreasonably refused to approve a plan that an overwhelming majority of our clubs voted to support, and that has received such widespread support from our fans and other members of the hockey community, including players," said Daly in a statement.
"We believe the union acted unreasonably in violation of the league's rights. We intend to evaluate all of our available legal options and to pursue adequate remedies, as appropriate."
The off-season relocation of the Atlanta Thrashers to Winnipeg in June forced the NHL to reconsider its divisional structure.
The new plan tried to address teams' travel concerns, as well as guarantee home-and-home series for every team and change the league's playoff format.
Shortly after the plan was approved, commissioner Gary Bettman said the NHLPA had expressed concerns but that the league didn't need the union to sign off on the changes.
Fehr rejected Bettman's claim and said the proposed plan would have fallen under the players' terms and conditions of employment in the collective bargaining agreement.
"We were prepared for the realignment from the NHL, but we weren't given every bit of information regarding it. How can you make an educated decision without all the proper information?" said Florida Panthers player representative Mike Weaver.
"We asked for the reasoning and that reasoning was not produced. They were not open to discussions about it."
The plan was to have two conferences with seven teams all based in the Eastern time zone: New Jersey, Philadelphia, Pittsburgh, New York Rangers, New York Islanders, Washington and Carolina in one and Boston, Montreal, Toronto, Ottawa, Buffalo, Florida and Tampa Bay in the other.
The third conference consisted of eight teams in the Eastern and Central time zones: Detroit, Columbus, Nashville, St. Louis, Chicago, Minnesota, Dallas and Winnipeg.
The fourth conference had eight teams in the Mountain and Pacific time zones: Los Angeles, Anaheim, Phoenix, San Jose, Vancouver, Calgary, Edmonton and Colorado.
Players reacted warmly to the changes in December, but some expressed concern with the increased travel during the regular season.
The uneven conferences, which featured two made up of eight teams and seven teams in the other two, were also contested since the number of teams qualifying for the playoffs would have been four in each conference.
"I was surprised to hear that it didn't go through," New Jersey captain Zach Parise said. "I didn't like the change in the playoff format, so it's not bad for us. But I know some teams are going to be upset with the travel. I personally like it the way it is and didn't want any changes."
The union's move to block the plan won't be welcomed in Winnipeg, with the Jets facing another travel-heavy year in the Southeast Division.
The team had no comment on the delayed realignment when contacted by The Canadian Press on Friday, but Jets co-owner Mark Chipman planned to address the delay at a news conference Saturday.
The lost plan also sets an uneasy tone to the start of labour talks, which were expected to begin after the all-star weekend later this month but are essentially underway now.
The collective bargaining agreement is set to expire Sept. 15.
— With files from The Associated Press.