The NFL used its flex-scheduling powers for the first time Tuesday, moving the Week 12 game between the 8-2 Packers and 8-1 49ers into the prime-time NBC slot on Nov. 24. The Seahawks-Eagles game, which tentatively had been scheduled for “Sunday Night Football,” instead will air at 1 p.m. Eastern on Fox that day, giving the league and its broadcast partners marquee matchups in each of its Sunday time slots: Seahawks-Eagles early, Cowboys-Patriots in the late-afternoon slot and Packers-49ers in prime time.

It’s probably not the last time the NFL will alter its prime-time schedule this season, but before we peer into the crystal ball, it’s best to go over the NFL’s flex-scheduling rules for games played in Week 11 or later:

Only games originally scheduled for Sunday afternoon may be moved into the prime-time spot. Games scheduled for Thursday, Saturday and Monday nights are untouchable.

Flex-schedule changes will be made no later than 12 days before the game day in question. For Week 17, the league can announce flex-schedule changes six days in advance.

Starting in Week 11, Fox and CBS can protect one game in five of the next six weeks, keeping those games in their Sunday afternoon time slots. They cannot protect any games in Week 17. The networks must submit those protected games to the league after Week 5 in most seasons.

No team is allowed more than six prime-time appearances per season and only three teams are allowed to have six prime-time games. No team may play in the Sunday night game on NBC more than four times (Week 17 is exempt from those limits).

Week 13, Sunday, Dec. 1

Scheduled Sunday night game:

Patriots at Texans

Flex possibilities (if not protected): 49ers at Ravens (Fox), Raiders at Chiefs (CBS).

Chances it gets flexed out? Slim! With three games on Thanksgiving that week, the league has fewer contests to choose from.

Week 14, Sunday, Dec. 8

Scheduled Sunday night game:

Seahawks at Rams

Flex possibilities (if not protected): 49ers at Saints (Fox), Chiefs at Patriots (CBS).

Chances it gets flexed out: Chiefs-Patriots was probably an auto-protect for CBS the moment the NFL released the 2019 schedule: It’s not letting an AFC championship game rematch between the dominant franchise of our era and the league’s most exciting quarterbacks get taken away. Likewise, Fox probably put a lock on 49ers-Saints considering its alternatives that day. The Seahawks have an MVP candidate in Russell Wilson.

Week 15, Sunday, Dec. 15

Scheduled Sunday night game:

Vikings at Chargers

Flex possibilities (if not protected): Seahawks-Panthers (Fox), Texans-Titans (CBS), Bills-Steelers (CBS), Rams-Cowboys (Fox).

Chances it gets flexed out: Is anyone truly excited about watching the currently 4-6 Chargers in prime time? Fox seems likely to have put the kibosh on Rams-Cowboys, but Seahawks-Panthers could be worthy of the spotlight, as could Bills-Steelers, with the latter a possible showdown for AFC wild-card positioning if Pittsburgh can keep up its surge.

Week 16, Sunday, Dec. 22

Scheduled Sunday night game:

Chiefs at Bears

Flex possibilities (if not protected): Cowboys-Eagles (Fox), Saints-Titans (Fox), Panthers-Colts (Fox).

Chances it gets flexed out: It’s hard to see the NFL wanting to keep the stumbling Bears in prime time for the penultimate week of the regular season. But the league also boxed itself in a bit on Tuesday when it also announced the schedule for the three Saturday games in Week 16: Texans-Bucs, Bills-Patriots and Rams-49ers. Those latter two games, especially, would probably be candidates for “Sunday Night Football” but now have protected Saturday status. Cowboys-Eagles on Fox is now the obvious choice, though one has to think Fox protected it, leaving Saints-Titans and Panthers-Colts as the choices to move to prime time.

Week 17, Sunday, Dec. 29

Best games: Steelers-Ravens (CBS), Saints-Panthers (Fox), Titans-Texans (CBS), Colts-Jaguars (CBS), 49ers-Seahawks (Fox)

As of now, all of the Week 17 games are scheduled for the afternoon, and the NFL may ultimately decide to keep all those games there if there are no games with massive playoff implications. But Monday night’s thriller between the 49ers and Seahawks could have the league salivating for a rematch — especially if it will decide the NFC West title.