The NFL's schedule release has become an event in itself. Each spring, all 32 teams officially find out when and where they'll face their opponents for the following fall and winter -- and for the most part, those games wind up being played exactly as planned.
However, that can't be said of every NFL matchup. The league has unique "flex scheduling" rules that allow it to alter its schedule during the season, with the primary goal of getting better matchups in primetime slots. As the NFL season and its storylines develop, the league is able to "flex" the matchups ahead of time into different slots.
There are specific rules that come with flex scheduling, though. The NFL cannot just alter its upcoming schedule however it wants, facing deadlines for changing certain game-viewing windows throughout the season.
Here's an in-depth breakdown of how the NFL's flex scheduling works.
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What is NFL flex scheduling?
Since 2006, the NFL has carried the ability for "flex scheduling" — which means that while the following season's schedule would continue to be solidified each spring, the league would be able to alter the schedule to move games into different time/day slots during the season, but still well in-advance.
As of 2025, flex scheduling is primarily focused on the "primetime" slots that allow teams to soak up the spotlight: Sunday night, Monday night and Thursday night. However, the league also makes sure to not announce Week 18 days/times for matchups when the rest of the schedule is released, leaving open a "flex" schedule so that it can get the most interesting games in the right slots for the end of the regular season.
Generally, the NFL will flex a week's primetime schedule over two weeks in advance, outside of Week 18. Because of NFL flex scheduling, there is never a full, 100 percent chance that a certain matchup remains in a primetime slot as the season develops -- although the league does face limitations for flex scheduling and generally tries to prevent from using its abilities.
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How does NFL flex scheduling work?
Here's what to know about the flex schedule process.
When can NFL games be flexed?
The NFL faces specific windows for when it can flex a game in or out of a primetime slot, which generally depends on the period of the season and which game window its attempting to flex.
The league will consult with networks throughout the process, but the absolute latest a can be flexed is six days in advance. For the most part though, flex scheduling will happen before that time frame. Week 18 is the only time where its guaranteed teams will not know their schedule until the conclusion of the prior week.
Which NFL games can be flexed?
Up until 2022, flex scheduling only applied to "Sunday Night Football." Now, games on "Monday Night Football" or "Thursday Night Football" can also be flexed in or out of those slots as well.
A Sunday afternoon game with a kickoff time of 1 p.m., 4:05 p.m. Or 4:25 p.m. ET time can be moved into any of the three weekly primetime slots, if the NFL flexes a game out of those slots. The game that was originally scheduled for primetime is then moved to Sunday afternoon.
Sunday afternoon networks (CBS and Fox) do carry a limited ability to protect games from being moved out of their slot, outside of Week 18.
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NFL flex scheduling rules 2025
The timelines for flex scheduling rules largely depends on which day the original game is scheduled, and how far in advance the game is.
Here's the specific flex scheduling rules by prime time slot:
Sunday Night Football
Flex scheduling for "Sunday Night Football" on NBC is able to be used by the league twice between Weeks 5-10, then anytime between Weeks 11-17. Generally, "SNF" sees more games flexed in or out than Monday/Thursday night, as it's simpler for the league to move a Sunday afternoon game into a Sunday night game, and vice-versa.
For "Sunday Night Football" games between Weeks 5-13, the NFL must provide 12 days notice before flexing. From Weeks 14-17, that time period shrinks to six days advance for flexing.
Monday Night Football
As for Monday night games, the NFL faces a shorter window than Sunday night — it is only able to flex a "Monday Night Football" game between Weeks 12-17 of the season.
All Monday night flex scheduling changes have to be finalized at least 12 days in advance of the game.
Thursday Night Football
"Thursday Night Football" has the strictest restrictions of the three primetime slots. The NFL can only move games in and out of that slot between Weeks 13-17.
Additionally, any "TNF" changes must be finalized by the league 21 days in advance.
Sunday afternoon
A Sunday afternoon NFL game with a kickoff time of 1 p.m., 4:05 p.m. Or 4:25 p.m. ET time is eligible to be moved into any of the three weekly primetime slots. If a change is made, then the original primetime game is moved to Sunday afternoon.
While it doesn't happen too often, games can also be moved from 1 p.m. ET to either 4:05 p.m. Or 4:25 p.m. ET and vice-versa. That was the case in Week 6 of the 2025 season, when Patriots vs. Saints was moved from 4:25 p.m. To 1 p.m. ET, while 49ers vs. Buccaneers was swapped into the later slot.
Week 18
Week 18 of any NFL season is a "flex schedule" in itself. The league does not announce the days or times for Week 18 matchups late in the regular season.
For the final week of the regular season, the NFL has a six-day notice to flex the schedule. The two Saturday games in Week 18 must be decided by the prior Monday.
Because "SNF" winds up being the final game in Week 18, the slot typically waits until most or all Week 17 games are over to find the most interesting matchup, with likely playoff implications, to close out the regular season.
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Why did the NFL introduce flex scheduling?
The NFL introduced flex scheduling in 2006. As it notes on its website, the league has the goal to "promote quality matchups on Sunday nights and give surprise teams a chance to play their way onto primetime."
Flex scheduling allows the NFL to get its most interesting matchups into primetime slots for the most fans to see. In a way, a team can "play its way" into a late-season primetime game by surpassing expectations for their season, then earning a flexed primetime slot.
For example, if two teams enters the year viewed as potential Super Bowl contenders and are given a primetime slot late in the season, but the teams then struggle to live up to those expectations, the NFL can put a more interesting game for playoff implications into the primetime slot.
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NFL flex scheduling history timeline
2006: NFL introduces flex scheduling
In 2006, the NFL introduced flex scheduling for the first time — but it was only created for "Sunday Night Football" initially.
For the last seven weeks of the regular season, the league was able to adjust its Sunday night matchups, aiming to get the most exciting games into that slot.
2014: Sunday night flex window extended
Eight years after creating flex scheduling, which still only included "SNF," the NFL lengthened the weeks in which it could change the premiere Sunday night matchup.
Upon the rule change, the league was able to flex the Sunday night game from Weeks 5-17, which remains the case today. Prior to then, "Sunday Night Football" was only flex-eligible in the last seven weeks of the regular season.
2023: Flex scheduling opens for Monday nights and Thursday nights
In 2023, the NFL made significant changes to flex scheduling by allowing Monday and Thursday night games to be flexed for the first time.
For nearly two decades, only Sunday night games had been flex-eligible. With the rule change, the Monday and Thursday night networks could work with the league to find more exciting matchups later in the season
2024: First-ever Thursday night flex
It wasn't until 2024 that a "Thursday Night Football" game was changed during the season.
In Week 16, a matchup between the Cleveland Browns and Cincinnati Bengals was removed from Amazon's Thursday night coverage, swapped to Sunday for a Denver Broncos vs. Los Angeles Chargers game.
2025: Deadline for Thursday night game flex changes shortened
Most recently, the NFL tweaked the rules for its Thursday night flex eligibility. Before the rule change, the league had 28 days to change a "Thursday Night Football" matchup before it would be solidified.
Under the change made at an owner's meeting vote, the NFL now has 21 days-notice to make a Thursday night change, giving the league an additional week to decide if it wants to change a "TNF" game.
Still, Thursday nights remained on the longer end for flex scheduling deadlines because of the traveling and preparation difficulties a short practice week causes NFL squads.
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