To the naked eye, Harris Andrews has appeared to be a quicker, fitter version of the man who was below his best form last season, but Brisbane's co-captain says perception falls short of the reality.

Andrews has re-established himself as one of the best key defenders in the AFL this year and is right in the thick of All-Australian conversations alongside Darcy Moore, Sam Taylor, Aliir Aliir and Callum Wilkie.

There's little doubt he's having more impact on games in 2023 than he did in the previous two years. He's fifth in the League for intercept marks (75), has more spoils than any other player (200) and is among the leaders for contested defensive one-on-ones.

He is also sitting just outside the top 20 of the AFL Coaches Association MVP Award with 47 votes, polling in nine matches, an impressive return for a key defender.

Quite simply, he anchors Brisbane's defence.

But ahead of Friday night's blockbuster against Collingwood, Andrews is quick to credit the Lions' system and their revamped backline as the reason for his return to top form.

He says the swap of Jed Adcock (from forward to defence) and Murray Davis (from defence to forward) as line coaches during the off-season has worked wonders for both ends of the ground. Adcock has the defenders playing more of a "system" and Davis has the forwards buying into team defence, which in turn has allowed Andrews to use his strengths in the back third of the ground.

"The game's so quick, and teams want to go quick and overlap run and move the ball fast," he says.

"We spent a lot of time over summer working on team defence ... there was a massive emphasis on that.

"The Tigers defence was unbelievable in their premiership years, Geelong's defence last year, incredible. Melbourne before that. We have to get to that level. A lot of guys put in a lot of hard work and that makes life easier for their backs.

"What can happen now is you can be a bit more proactive and you can think quicker and not just rely on physical attributes.

"You can work on the mental side and anticipate what's happening and that's probably helped me.

"Maybe in the past we were a bit more on one-on-one, where you rely on your physical attributes. There's so many great forwards that have great physical attributes and you can't always beat them that way."

Still just 26 years old, the Brisbane Academy graduate steadily improved following his 2015 debut, stamping himself as a force with back-to-back All-Australian jackets in 2019 and 2020.

But when the same influence did not follow in the following seasons, questions came about his fitness, his form and his desire.

Vision was pieced together of Andrews being beaten on the lead and sometimes being beaten in the air, leading to questions about whether he was still the same dominant force.

Always with the backing of coach Chris Fagan, the full-back says there was no particular reason for the perceived slide in form.

"You can get caught up listening to anyone and everyone," he says.

"I'm not running around in my first season looking for pats on the back with how I'm going. It's just important to listen to the people I trust like my teammates and my coaches and whether I'm fitting into our system.

"There's (been) no injuries over the last few years. I haven't had any ailments stopping me from moving the way I want to move.

"Sometimes forwards get you, but that's the game. I'm always striving to get better and not be content with where I'm at."

Not only has Brisbane implemented a more proactive defensive system this season, it has had to do so with a few new faces.

With Marcus Adams unavailable through concussion, Darcy Gardiner battling injuries and Daniel Rich sliding out of the senior team, some of the regulars from previous years have no longer stood alongside Andrews.

Jack Payne has locked down the key post alongside his co-captain, Conor McKenna has exceeded expectations in his first year back in the AFL and Darcy Wilmot has added run-and-dash in attack and closing speed to clean up mistakes in defence. Then there's Ryan Lester, who is playing the best football of his career in season No.13.

The results have been telling, with the Lions conceding the second fewest inside 50s this season as they eye a top-two finish and a run at a premiership.

Andrews says he is ready for anything against the Magpies on Friday night, including a scenario where Jeremy Howe plays a negating role on him.

It was a tactic Gold Coast used with Ben King a month ago, with the young Sun not only stopping Andrews from taking intercept marks, but kicking five goals himself.

"I did a hell of a lot wrong that night, but it was a great lesson for me," Andrew says. "They looked to play a bit more defensively on me and that was an eye opener.

"You have to go into the game with all options open. I've got to be aware and ready for them.

"Friday night is going to be really exciting. They're on top of the ladder for a reason.

"I've really admired the way they've gone about their footy. I'm a bit of a footy tragic and to see the energy their crowd brings is an exciting prospect for us.

"It's going to be a really good challenge."

If there's one thing Andrews has shown in his nine seasons, it's that he loves a challenge. The challenge of being drafted as a forward and moving into defence. The challenge of being criticised and bouncing back to his best.

And ultimately, the challenge of lifting Brisbane to its first premiership in 20 years.