While the grunt work is typically done by the midfield of an AFL side, the heavy lifting can often be done by the backline, especially for teams at the lower end of the ladder.
Premiership defences require potent key defenders, intercepters and running ball-users to provide an offensive threat.
Geelong were an unstoppable force out of defence last season, with De Koning and Stewart constantly preventing chaos and allowing ThuoyThou, Guthrie and others to control the ball effectively.
Melbourne were unbeatable at their best in 2021 with Lever, May, Petty and even Gawn maintaining control of the game with their aerial presence while Salem, Brayshaw and Rivers inflicted damage by foot.
This list will help you decide which team will be the immovable object in 2023 and here we look at the backlines ranked 12-7.
SEEL: Every AFL team's backline ranked PART I
This side may still be living off the glory of 2018, but the premiership talent is still there in 2023, especially through the backline.
Jeremy McGovern, Elliot Yeo and Shannon Hurn have been thriving off their reputation more than their gameplay in recent seasons, but 2023 will provide a fresh start that has seemingly been absent during the last few COVID-19-struck years.
Tom Barrass has developed into one of the best key defenders in the competition after a stellar 2022 season which was capped off with a club best & fairest.
Tom Cole and Liam Duggan are reliable medium-sized defenders who also featured in that historic 2018 victory.
Beyond their premiership heroes, the Eagles have found themselves spoiled for choice in defence after an active off-season.
Jayden Hunt may prove to be a big acquisition given he has been a notable pre-season performer. Number nine draft pick Reuben Ginbey looms as a future star who will be a handy addition to this year's backline. Campbell Chesser is awaiting his opportunity to run off half-back while Brady Hough may be trialled after a positive summer and debut season.
Alex Witherden, Sam Petrevski-Seton and Harry Edwards will all fight for a spot while Rhett Bazzo, Jemaine Jones, Luke Foley, Callum Jamieson and Tyrell Dewar round out the defensive depth charts.
On paper, the Giants' defensive list is up there with the elite backlines of the competition, stacked with reputation, potential, and star power.
At the forefront of that star power is full-back Sam Taylor, fresh off receiving a maiden All-Australian blazer and looking every bit as good as last year during his preseason.
By his side is Nick Haynes who has proven to be an All-Australian calibre defender himself, and Connor Idun who could be set for a breakout 2023 season given his development.
Phil Davis and Lachlan Keeffe are the experienced veterans who are hopefully not required but add to their key defensive depth nonetheless.
At ground level, Lachie Whitfield, Lachie Ash and Isaac Cumming are all established or potential stars who are expected to perform this season in a rejuvenated side led by Adam Kingsley.
Several young players will be looking to break into the senior side or show positive development for the future. Leek Aleer has shown his ability in the pre-season while, Josh Fahey firms as a potential debutant.
Harry Himmelberg displayed his versatility last season and could also add to the Giants' defensive depth if required.
The Bulldogs are stacked with top-end talent all over the ground even after losing stars Josh Dunkley and Lachie Hunter. Perhaps the biggest knock on this side last season was their lack of an elite key defensive presence and this problem looks to have been solved with the addition of Liam Jones.
He will take significant pressure off Alex Keath and Ryan Gardner by taking the opposition's best forward, allowing them to display their ability as second and third options rather than being options one and two.
Ball users Bailey Dale and Caleb Daniel are stars of the competition and will continue to provide an offensive threat out of defensive 50. With talks of Daniel potentially taking on an inside mid role, Ed Richards may be asked to step up his production down back also.
Jason Johannisen still hasn't matched the elite form he showed in 2016 but is yet another running half-back option this year while Taylor Duryea and Hayden Crozier will also be eyeing off a spot in the side with their defensive capabilities.
One exciting watch is the continued development of swingman Sam Darcy as he navigates his role in the side. Bailey Williams will also be looking to return to his previous form after he showed some elite decision-making ability in 2021.
The Power have a steady mix of talent on their defensive line and were able to prevent big scores from their opponent last season, conceding only 74.4 points per game.
They have the capacity to limit opposing power forwards with Aliir Aliir being one of the league's best intercept defenders when healthy while Tom Jonas and Tom Clurey round out an effective tall defender slot.
Darcy Byrne-Jones and Dan Houston carry the load at ground level and are both coming off quality seasons with Houston's offensive launch and Byrne-Jones' lockdown ability.
Ryan Burton and Riley Bonner will have an intriguing battle for the final spot in the back six throughout the year, they both provide some extra handy ball use out of defensive 50.
Jase Burgoyne and Lachie Jones add to their depth and are notably popular choices to round out the back options.
This Richmond side does not have the same defensive presence as they did in their premiership years, but Tigers fans will hold faith in their experience and system.
Robbie Tarrant had a solid first year in the yellow and black but is probably not a desirable number-one key defender on a premiership team. Dylan Grimes and Noah Balta, however, provide excellent backup which could make up for any tall defensive deficiencies.
Daniel Rioli and Liam Baker also provide an excellent presence as small defenders and back-line ball users, both being able to roam forward as a goal threat. Jayden Short may also play this role when resting from a midfield spell.
Nick Vlastuin, Nathan Broad and sophomore Josh Gibcus are all quality defenders who may be tussling for a spot in the back six; all would be stiff to miss out given their ability.
Beyond that, Richmond are stacked with young players capable of playing down back when their time comes. Hugo Ralphsmith, Sam Banks, Tom Brown, Rhyan Mansell, Bigoa Nyuon, Kaleb Smith and Tylar Young will all be in for a year of development while their side looks to contend.
While the Lions potentially have the most talented overall list in the competition, if there is a weakest link, it is their backline.
The one potential knock on their 2023 defensive list is their key defender depth, especially after losing Marcus Adams for the season. Harris Andrews is still one of the truly elite defenders of the competition and put many doubts to bed after his finals performances against Richmond and Melbourne.
However, Jack Payne and Darcy Gardiner are unproven at the highest level and may be exposed when opposing forward lines present a potent double threat in the key forward category; see Geelong and Carlton.
Brandon Starcevich has gradually developed into one of the premier medium-sized defenders in the league and can be backed up solidly any day by Deven Robertson or Noah Answerth.
On the offensive side, Daniel Rich remains a point of difference with his dangerous left leg out of defensive 50, while Keidean Coleman is highly rated internally and could be in for a big year with his ball use and decision-making.
Conor McKenna may struggle to find his footing in the early parts of the season but footy fans know what he can do with his exciting run and dash. Plenty of SuperCoach players will be betting on his success as well as Darcy Wilmot, who firms as another option off half-back if not on a wing.