(adapted from a comment)
Refer to this thread for a good background on flex rules in 2013: http://boards.straightdope.com/sdmb/showthread.php?t=702437
A team can only be shown in primetime 5 times a season.
But, of the teams that have five games in a given year (this year: DEN, NE, ATL, NYG, SF, WAS), three of those can be flexed into a sixth late-season primetime game. In other words, they don’t want the rules to hamper them if a matchup is too juicy to pass up. Usually though, the flex matchup is not only "juicy", but comes in a week where the previously scheduled game turns out to be a real stinker. Like last weeks Scott Tolzien vs. a NYG team that strated 0-6 game they flexed out of. So, if there’s a potentially better matchup, but there’s already a mediocre one scheduled (say at least one playoff contender and relatively large fanbases), they’ll usully keep it. Also, MNF and TNF games and teams cannot be flexed and CBS and FOX can each pick one game a week to protect from flexing.
Let’s look at the possibilities for flex games coming up. We already know for certain because of the 12-day rule that the next matchups are DEN-NE and NYG-WAS:
Week 14: ATL @ GB.
They already flexed out of the Pack’s last appearance this past week. Would they do it to one of the NFL’s most popular franchises again 3 weeks later? Yes, especially if Rodgers still isn’t back and the Packers slip further out of the playoff picture.
Possible Flexes: CAR-NO, DET-PHI, SEA-SF
I know you said you think that SEA-SF cannot be flexed, Cuenca, but I have not found anything to support that notion. It would be SEA’s 5th game in primetime and SF’s 6th (permitted). Broncos have already maxed out to 6 by getting on last week, so picking this game would mean two things: Out of NE, ATL, NYG and WAS, only one more game featuring any one of those teams could be flexed into the rest of the season, and Two: the ARI-SF game could not be flexed week 17 (bad news for us). My guess is still with the darkhorse game: CAR-NO (FOX protects SEA-SF, or if they protect CAR-NO, SNF picks up CAR-NO or DET-PHI), and I think they definitely flex.
Week 15: CIN @ STL
Cincy is a division leader and PIT while having a down season is still not out of it in the AFC and has a large fanbase. I don’t think they flex (maybe they would have if PIT had one or two more losses or CIN had CLE’s record)
Possible Flexes: Really nothing doing here. BAL-DET is already MNF. What else would they put here? NE-MIA (yawn)? KC-OAK (haha)? Niners-Bucs (no)? Bills-Jaguars (kidding…)? I’ll put this at about a 1% shot, with Jets-Panthers in the lead. Really, about the worst week for a possible flex you could have dreamt up. Do yourself a favor and look up the spate of games for this week, it ain’t pretty.
Week 16: NE-BAL
Can’t see them taking Brady off the air, esp when the Ravens have a token playoff shot (OK, maybe a bit more than that, but still, they’re not last year’s team).
Possible Flexes: That said, there are some interesting possibilities here if they decide to go that unlikely route: NO-CAR (if they don’t flex the first matchup), ARI-SEA (we’d all like to see that, but probably not sexy enough nationally). Colts-Chiefs or Bears-Eagles would probably be the most likely candidates if anything were to happen.
Week 17: Open
Here’s where it gets fun. The NFL wants a matchup that is guaranteed to have playoff implications, preferably for both teams. Therefore, it’s hard to predict this one this far out as a lot of teams will have been eliminated going into this week that are alive now.
Let’s group these into a few categories based on what we know at this early stage. I’ll rank these games from ones with the least attractiveness (no potential playoff teams going into week 17) to most (two potential playoff teams, better yet ones with large fanbases, and best of all, games that could potentially act as a play-in game with the winner punching a ticket and the lose going home)
Least attractive, in no particular order (less than 2% chance):
CLE-PIT (OK, maybe PIT is competing for a sixth seed at that point, but probably not and they definitely won’t flex in Cleveland no matter what)
One Playoff team, potentially with nothing to gain (and prob. not playing starters) playing a non-playoff team (less than 5% chance)
There may be some seedings at stake here, but that’s usually never enough to justify putting a non-playoff team on because of a chance to "play the spoiler" and change someone from a 3 seed to a 4 seed.
Most attractive (great than 50% chance it’s one of these) these are ranked in order based on what I PROJECT to happen:
We all know they love the NFC East, and that it’s shaping up to be a down-to the wire division this year. There’s a good chance both teams are somewhere around 8-7 or 9-6 going into this game with a "win-and-you’re-in" scenario coming into effect. Those two factors far and away make this the most likely candidate.
2. tie – SF-ARI
The one we all want! There’s a good chance the 6-4 Niners go 3-2 or 4-1 in their next five (Possibly 1-2 losses next three weeks @WAS, STL, SEA, and then @TB, vs. ATL. If SEA is almost a surefire loss for them, then they can come into their game with us no better than 10-5. It’d mean we’d have to run the table between IND, @PHI, STL and @TEN, or beat @SEA if we dropped one of those. It’s doable, but then we’d also have to root for SF to lose to SEA at home (not guaranteed). All we have to do is keep pace with the Niners the next 5 weeks. We can afford to lose a game as long as they do too, and we both play Seattle. A potential windfall for us may be Seattle resting starters against us in week 16. For that to happen we need to start rooting for them to beat the Saints next week – and then turn around and root for the Saints to beat the Panthers twice. If we do get this scenario, expect this to be a very appetizing one for SNF, although PHI-DAL or GB-CHI would certainly "win the tiebreaker" (more popular teams) if they also were in the same scenario.
2. tie – GB-CHI
This one would be higher up the list if Rodgers was coming back before Thanksgiving, but he isn’t. Bears will have 8-10 victories by this point and even if Rodgers comes back late this year they may be looking at 8-9 wins in the very best scenario. That still makes it a juicy matchup well within the realm of possibility of being flexed, but I just don’t see the Pack salvaging that ship in time. This rockets ahead of SF-ARI if they achieve that very best scenario, though. The NFL loves the GB-CHIrivalry, and it could very well then be a play-in game.
There’s a small chance they could both be the leaders for that 6th seed in the AFC that no one seems to want. They play each other once before week 17 as well. Both teams likely come into this game with around 7-8 wins if it is to determine a playoff spot, even then, it’ll look like two teams backing in, and it might end up being one team with a shot to clinch with some help and one team already eliminated. Better shot than some others in this category (i.e. BAL-CIN), but still not great.
Looking at their remaining schedule, Ravens are likely no better than 7-8 going in to this one. Unfortunately for them, Cincy is likely no worse than 10-5 or 9-6. I put this one on here because of the off shot that the Ravens could get hot and come in with 8 or 9 wins and Cincy could falter and have the same (They have 7 wins with 5 to play), but don’t hold your breath.
KC is a surefire playoff team playing a potential 6 seed and division rival. This sounds intriguing, especially if SD can come in with 7-9 wins although even then the storyline would be "Can KC, with the 5 seed already locked up keep a division rival from the other wild card?". The one impediment to this "meh" matchup (as far as week 17 SNF games are concerned)? SD is already 4-6 and has to play @KC, CIN and @DEN before that. They’ll most likely already be out by that point.