YOUNG Geelong star Connor O'Sullivan has taken the same focuses into all three of his AFL pre-seasons, making steady progress that has left him feeling well prepared to take on the game's biggest forwards in 2026.

After making a massive jump in 2025 and emerging as one of the game's brightest young defenders in just his second season, O'Sullivan tripled down in getting bigger, more powerful, and faster off the mark over summer. 

A pre-season spent testing himself against teammates Jeremy Cameron and Shannon Neale has left the 20-year-old feeling confident that he can take another big step as a key defender, starting on Friday night against Gold Coast's talls. 

"The things that I was working on from my first year to my second year are the things that I want to be working on again, and I feel like they're long-term goals to become more powerful and stronger as a player," O'Sullivan told AFL.com.au on the eve of his third season. 

"I want to be able impact contests as much as I can and be as physical as I can, so they're the main focuses.

"Going from one game (in 2024) to 25 games, it's very fatiguing and it was nice to relax for a couple of weeks and reset mentally and physically. But since we got back, it's been about how strong I can get and how well I can work on my craft as an aerial player.

"I'm trying to get as heavy as possible (and) I'm feeling a lot stronger in the gym."

Among his 25 games last season, O'Sullivan played in all three finals and showed composure on the Grand Final stage, with the experience teaching him about the higher intensity of finals and the physical preparation needed to stand up in those games.

The ability to also play on established key forwards throughout the season has fast-tracked the young Geelong backman and quickly turned him into a key player for the perennial contenders.

Recognition followed, with O'Sullivan placing fifth in the Telstra AFL Rising Star, winning Geelong's best young player award, and signing a contract extension through to the end of 2028.

"Coming in last year and seeing the jump between the standards was good for me to understand what it really takes to be a good key defender in the competition," O'Sullivan said.

"It's just about building consistency and how many times you can come up against guys like (Charlie) Curnow and really challenge them and win battles.

"[Those match-ups] probably do fast-track you a little bit because you understand the standards a little bit more and what it takes."

As well as learning from the game's best forwards, O'Sullivan highlighted the impact his backline teammates were having on his development. When it comes to opposition key defenders, Greater Western Sydney gun Sam Taylor and dual Brisbane premiership captain Harris Andrews are the two stars he watches closely to help shape his own game.

There is more to O'Sullivan than simply stopping his opponent, however, with the athletic tall open to evolving his skill-set in different ways and in different roles throughout his career.

"My goal is to be a good or a great key defender, and whether that allows me to be a bit more versatile and able to change roles and do other stuff on the ground, I would love to," O'Sullivan said. 

"I look at 'Blitz' (Mark Blicavs), and he's probably the best example there is with how he's moulded his game over time, and whatever roles is asked of him, he does it to the best of his ability.

"So for me, right now, it is primarily being a key defender and I'd love to build that and become the best I can at that.

"But in terms of what a role looks like in the future, I'm open to anything and would love to be as good as I can anywhere that Scotty (coach Chris Scott) and the team sees me."

While O'Sullivan was drained at the end of last season, a holiday to Europe, taking in a Champions League game between soccer giants Real Madrid and Juventus, and spending time in Italy with his partner helped the Albury product return fresh and excited for his third season. 

There had been a change to Geelong's coaching structure when he returned, with former Collingwood coach Nathan Buckley a new addition to Scott's team. Buckley has brought a set of expectations and standards that are resonating with the young defender. 

Part of that expectation is for O'Sullivan to continue growing as a young leader after the 198cm defender and sports management student proved his ability to be a vocal player who can give teammates clear direction.

A tight bond with the players from his draft class, including Lawson Humphries and "big brother figure" Shaun Mannnagh has allowed him to feel comfortable in the team and be himself on the field.

"I really do value the leadership side of the game… and my voice and ability to try and connect with my teammates out on the ground," O'Sullivan said.

"For me it can not only be reassuring as a player hearing voice, but I take a lot of reassurance in communication and it keeps me in a frame of mind of where I need to be in the game and allows me to stay focused.

"That hopefully helps others, so I do really value that aspect of the game and want to keep developing that."