But the truth is, unusually for rugby league - a game in which there is generally no such thing as a well kept secret - that no one really knows.
Most pundits will tell you it's the existing 12 plus any two from the unholy trinity of Celtic, Salford and Widnes.
But that's about as close as you will get ahead of Tuesday's big announcement.
You can make solid cases for and against a few teams.
Of the existing 12, Cas are on the thinnest ice because of ramshackle old Wheldon Road.
No one really expects the Tigers to get the boot, but they might be the subject of some kind of conditional licence, based on them escaping to a new ground within a year or two.
Ditto Salford, whose new home at Barton still looks suspiciously like a muddy field to me.
My views on Celtic are well known, but if the RFL don't dive headlong into the valleys now they might never get another chance if Crusaders backer Leighton Samuel takes his oval ball home with him.
Then there's Widnes, bust last September, but now apparently a picture of financial health.
Personally, I reckon Widnes and Salford will get the nod. Although I wouldn't be willing to stake my shirt, or even an odd sock, on that one.
For what it's worth, I also think Fax are closer than anyone thinks.
But the reality is that this whole disagreeable process has probably arrived 12 months too soon for them.

I KNOW we're biased, but you'd be hard pushed to find anyone in Halifax who could name someone more deserving of a prize for their contribution to rugby league than Hilda Hardy.
Hilda, and the dozens of other people like her at clubs across the country, doesn't score tries, doesn't make the headlines - at least not until now - and doesn't take home a gigantic wage packet.
But without Hilda, and her late husband Stan, clubs like Halifax just wouldn't be able to function.
To put it bluntly, Fax just wouldn't be Fax without Hilda. Just as it hasn't been quite the same since Stan, with his cutting, acerbic wit and occasionally agricultural language, died in 2006.
Which is why, in an era when the sport is diving headlong into a world of corporate soullessness, it was hugely refreshing to see Hilda step up at the George Hotel, alongside more conventional luminaries like Mike Stephenson and Ray French, and be recognised for the years of service she has given to Fax and the game as a whole.
Thank goodness the RFL had the wit and wisdom to look outside the box, to find someone other than the usual suspects to share the limelight.
Someone at Red Hall, who is obviously well acquainted with Hilda's hours of toil and has the clout to help make these things happen, deserves a big pat on the back.