A look at the likely round one line-ups for all 16 clubs shows that 15 of them will have at least one major change to their playmaking 'spine' from their favoured 2019 configuration.

Barring injury during the trials, Brad Arthur's Eels are set to start 2020 as the only club with the luxury of the same players in the 1-6-7-9 jerseys.

The Storm are the only other side that may start 2020 with their preferred combination from the end of 2019, if they stick with Jahrome Hughes at No.7.

However, it took them most of last year to get to that point with Brodie Croft starting the first 22 rounds at halfback.

The other 14 clubs have at least one significant change in a key playmaking role due to a combination of player movement or retirement, injury or expected coaching decisions.

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Even with five-eighth Dylan Brown missing a chunk of last season with a back injury, Parramatta's preferred spine – also including fullback and captain Clint Gutherson, halfback Mitch Moses and hooker Reed Mahoney – played 15 games as a unit in 2019, winning 10.

"Keeping the spine together is really important," Mahoney said.

"Going through the whole season last year, we were good but we weren't good enough.

"There were times through the year we weren't consistent as a spine. We always spoke about that, that we needed to be consistent and it's something we've obviously touched on in the off-season.

"When we're consistent and playing good footy everyone sort of flows off the back of that and we win football games."

Gutherson said with Brown just 19 and Mahoney 21, continued improvement should be expected.

"We've got youth on our side which is good. Another year, another pre-season, every session out there you're getting better," Gutherson said.

"Dyl's come [along] miles since last year and he was one of our best last year. It's exciting for us to be able to watch him grow as a player and as a person off the field. It's exciting and you'd like to think it keeps going up."

Brown said the confidence the players had already built in each other was an asset.

"Mitch can take control and he feels confident doing so; with me being young he takes control and I do what I can do, what's best for the team so I go off that."

Moses cautioned the team couldn't allow itself to believe its continuity would provide an advantage because every other side had been working all pre-season to ensure they hit the ground running with their new combinations.

"We'll have that game experience but they'll be working together in the pre-season," Moses said.

"I think Brad's just been really good for us at training, you can see he's a lot more calmer around training, I think he knows what we're trying to do and we've got full confidence in Brad that he's doing the right job. He's grown as a person and a coach as well."

NRL.com has ranked the 16 clubs from least to most disruption in their playmaking combination. The list does not consider the quality of club's playmakers, just the expected changes from 2019 to 2020.

2020 spines for all NRL teams

1. Eels

Clint Gutherson, Dylan Brown, Mitch Moses, Reed Mahoney. Unchanged from last year.

2. Storm

Ryan Papenhuyzen, Cameron Munster, Jahrome Hughes, Cameron Smith. Unchanged from the end of last year but this quartet only played four games together (Brodie Croft was the halfback for the first 22 rounds). Cooper Johns is making a push for the No.7 jersey.

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3. Sharks

Matt Moylan, Shaun Johnson, Chad Townsend, Blayke Brailey. Brailey replaces his older brother Jayden at hooker in the only change, and played 14 games as a bench hooker last year – meaning this combination already has experience together. This exact four-player combination started together once, in round 14, when Jayden was unavailable.

4. Bulldogs

Dallin Watene-Zelezniak, Jack Cogger, Lachlan Lewis, Jeremy Marshall-King. All four players were at the club last year, although they did not all start together in any one game. Kieran Foran (shoulder) is a big loss while Michael Lichaa and Nu Brown have left, Sione Katoa has joined and Brandon Wakeham will push for a start in the halves.

5. Sea Eagles

Tom Trbojevic, Dylan Walker, Daly Cherry-Evans, Danny Levi. If Manase Fainu (who is out with a shoulder infection and is also currently stood down) returns, the club can field the combination it ended last year with (Walker moved to the halves in round 18). Cade Cust and Lachlan Croker are still on the books.

6. Rabbitohs

Latrell Mitchell, Cody Walker, Adam Reynolds, Damien Cook. Coach Wayne Bennett never really settled on a fullback in 2019 with Alex Johnson, Adam Doueihi and Corey Allan all used. If Mitchell can gel with what is otherwise a settled and all-star spine the Rabbitohs will be a huge threat.

7. Canberra Raiders

Charnze Nicoll-Klokstad, Jack Wighton, George Williams, Josh Hodgson. Just one change but it's a big one, with livewire England half Williams replacing the steadier Aidan Sezer at No.7. Look for Hodgson to pull the strings even more than usual while the new structure beds down.

8. Roosters

James Tedesco, Kyle Flanagan, Luke Keary, Jake Friend. Like their grand final opponents, just one change, but a big one with Sharks youngster Flanagan replacing the retired Cooper Cronk in the halves.

There is also the matter of what to do with impressive young hooker Sam Verrills if Friend is fit after he played just six games last year.

9. Wests Tigers

Corey Thompson, Benji Marshall, Luke Brooks, Harry Grant. At the very least the Tigers need a hooker to replace Robbie Farah (retired) and Jacob Liddle (knee, mid-late season).

Moses Mbye has trained there after playing fullback the first half of last year while Storm youngster Grant could be the answer if his swap deal gets over the line. Corey Thompson finished last year at fullback but faces a challenge from recruit Adam Doueihi.

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10. Knights

Kalyn Ponga, Kurt Mann, Mitch Pearce, Jayden Brailey. The two main men are still there in Ponga and Pearce, while Brailey is the fresh face at hooker. Mann played a handful of games in the halves last season and will face pressure from the likes of Mason Lino and Phoenix Crossland if the team doesn't start well.

11. Dragons

Zac Lomax, Corey Norman, Ben Hunt, Cameron McInnes. The departure of Gareth Widdop is massive even though he missed a lot of 2019 injured. Lomax is set to displace Dufty at the back with Norman returning to the halves. Issac Luke may spend time at hooker with McInnes to float at lock or get a rest at times.

12. Warriors

Roger Tuivasa-Sheck, Kodi Nikorima, Blake Green, Wayde Egan. Issac Luke is gone, Nat Roache is out long-term and Jazz Tevaga is sidelined for the first month, leaving Egan as the likely hooker. It's also possible Nikorima plays there and Chanel Harris-Tavita starts in the halves. The fact the Warriors are still unclear where the latter two players will start shows there is plenty of uncertainty.

13. Titans

AJ Brimson, Tyrone Roberts, Ash Taylor, Nathan Peats. Fullback Michael Gordon has retired and half Ryley Jacks has returned to Melbourne. Taylor has returned from a mental health break, Tyrone Peachey has been training at five-eighth and Peats ended up job-sharing hooker with Mitch Rein last season and spending time at lock. Tanah Boyd is also pressing for more senior games in the halves.

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14. Panthers

Dylan Edwards, Jarome Luai, Nathan Cleary, Api Koroisau. Penrith have been crying out for a hooker since Peter Wallace retired and while Koroisau's return should help (following the departures of Sione Katoa and Wayde Egan), James Maloney leaves a massive gulf at five-eighth.

Maloney was very much the senior guiding half, despite Cleary being the NSW halfback. Luai is talented but has a long way to go to help Cleary fill that breach. Mitch Kenny's emergence should keep the pressure on Koroisau.

15. Cowboys

Valentine Holmes, Scott Drinkwater, Michael Morgan, Jake Granville. The return of Holmes adds some desperately needed spark to the North Queensland backline, pushing Drinkwater to either the halves or out of the side.

It appears the club is happy to take their time with Jake Clifford while there is a strong chance Reece Robson displaces Granville at hooker either at the start of the year or if the club starts slowly, which would mean only Morgan is unchanged from last year.

16. Broncos

Jamayne Isaako, Anthony Milford, Brodie Croft, Jake Turpin. Brisbane's finals capitulation against the Eels last year featured Milford at fullback, Darius Boyd at five-eighth, Turpin at halfback and Andrew McCullough at hooker. It is likely none of those players will be in those spots to start 2020.

Milford should return to the No.6 jersey he spent the first half of the 2019 season in, playing alongside recruit Croft. Isaako is set to take over at fullback, Boyd will be relegated to a centre/wing role and Turpin has made a strong case to take over from McCullough at hooker.