Looming over the whole thing was the breakdown in collective bargaining between the league and the NFL Referees Association (NFLRA). The contract expires May 31, and replacement officials are now a genuine possibility.

Here, DAZN News breaks down what was said, which rules and bylaws were amended, and what it all means.

Replacement refs: What the new rules mean

NFL commissioner Roger Goodell acknowledged negotiations with the NFLRA have not "progressed the way hoped from a timing standpoint."

In the event of a work stoppage, replacement referees may be introduced.

Two significant changes to the replay review system were approved, each with very different triggers.Monica Schipper / Staff

The first rule change only kicks in if a work stoppage is activated.

If replacement officials are used, staffers in the league's officiating command centre in New York will be able to consult with on-field officials on called and uncalled penalties.

That includes alerting a replacement referee to clear and obvious evidence of an uncalled foul for roughing the passer, intentional grounding, or an act that would normally lead to disqualification.

Staff members could also flag that a penalty should not have been called if video evidence shows that at least one element of the foul is not present.

Separately, and regardless of any work stoppage, replay officials in New York will, for the first time, have the authority to disqualify a player and direct that a penalty be enforced, even if no flag was thrown on the field, in the case of a flagrant football or non-football act.

Competition committee co-chair Rich McKay explained the thinking.

"If we're going to do this, we have to put a flag on, because we cannot have a fourth-and-2 show up; they disqualified a player from the previous play for a non-football act, he's punched somebody ... and the team still has to punt," McKay said.

Onside kick rule change 2026: Explained

Previously, the rule allowed onside kicks only in the fourth quarter, but the league will now allow them to be declared at any time during the game. 

Michael Reaves / Staff

The change came about partly because teams wanted the option when a penalty enforcement forced them to kick off from the 50-yard line.

It could significantly alter late-game strategy for teams trying to claw back a deficit.

Kickoff rule changes 2026: What's new

The league moved to eliminate the kicking team's incentive to intentionally kick the ball out of bounds when kicking off from the 50-yard line.

Alignment requirements for receiving team players in the setup zone have also been modified.

The NFL believes this could help address an increase in the concussion rate on kickoffs.

The 18-game season debate: Owners divided

The prospect of an 18-game regular season was another topic generating plenty of conversation in Phoenix, with owners and coaches divided on the idea.

Support among owners appears to be growing. Patriots owner Robert Kraft said he likes it "for the long-term growth and development of the league," adding he would personally like to see a second bye week introduced alongside any expansion.

Dallas GM/owner Jerry Jones is also in favour.

Chiefs owner Clark Hunt linked the idea directly to the league's international ambitions. "From a schedule dynamic, having 18 games would facilitate that," he said.

Not everyone is convinced. Browns owner Jimmy Haslam called the conversation "a little premature," while Saints coach Kellen Moore pointed to the sheer volume of games already on the calendar.

Any expansion would require CBA negotiations with the NFLPA, which has already stated its opposition. The debate is still in its early stages, but it's clearly underway.

Mental health coverage: New NFL requirements

Away from the playing rules, owners approved an expansion of mental health coverage.

Each team will now be required to employ a full-time clinician or offer full-time mental health coverage.

Eight of the 32 clubs are already in compliance.

The policy will also provide more support for players on injured reserve and is subject to approval by the NFL Players Association under the collective bargaining agreement.

Free agency calls, PUP list and rosters

Pittsburgh's proposal to make permanent the rule allowing clubs to have one video or phone call with up to five prospective unrestricted free agents during the Two-Day Negotiation Period was approved.

Players on the Reserve/Physically Unable to Perform list will be permitted to begin a 21-day practice period after the club’s second game of the regular season.

The league office will also be permitted to adjust procedures and dates for the final roster reduction to accommodate an international game in the first week of the regular season.