NFL owners have backed a new collective bargaining agreement (CBA) and invited the league's players to get the deal over the line.
Plans to expand the fixture schedule have proved a divisive issue amid a push for a 17-game regular season.
The existing deal expires at the end of next season and NFL commissioner Roger Goodell recently insisted player welfare continued to be a priority.
The NFL said in a statement on its website that the new CBA would "transform the future of the game".
Now, the NFL Players Association (NFLPA) will need to examine the terms on the table and give a two-thirds majority approval, before all players are then given the chance to vote.
Only then can the CBA be enacted, and there is no guarantee of the players' support. Initial talks within the NFLPA will reportedly begin on Friday.
Speaking last month, San Francisco 49ers cornerback Richard Sherman, who is an NFLPA vice-president, accused the NFL and team owners of putting a "price tag" on player safety in pushing for the extra game.
He and other suspect the move is a stepping stone to an 18-game season.
Sherman said ahead of the Super Bowl: "I don't think it's something the players are interested in, honestly. If that's the point they're negotiating on, I think these negotiations are going to go a lot longer than anticipated."
The NFL said in its statement on Thursday: "Following more than 10 months of intensive and thorough negotiations, the NFL players and clubs have jointly developed a comprehensive set of new and revised terms that will transform the future of the game, provide for players - past, present and future - both on and off the field, and ensure that the NFL's second century is even better and more exciting for the fans.
"The membership voted today to accept the negotiated terms on the principal elements of a new collective bargaining agreement. The Players Association would also need to vote to approve the same terms for there to be a new agreement.
"Since the clubs and players need to have a system in place and know the rules that they will operate under by next week, the membership also approved moving forward under the final year of the 2011 CBA if the players decide not to approve the negotiated terms.
"Out of respect for the process and our partners at the NFLPA, we will have no further comment at this time."
A report on the NFL website said the CBA proposal included an option for the future 17-game schedule, along with increasing the players' share of revenue from 47 to 48 per cent - reportedly rising to 48.5 per cent in the event of the 17-game season being implemented.
It also includes the plan to expand the play-offs to make it a 14-team competition, starting immediately.