FOOTBALLERS spend more time planning than playing. They scour tapes of themselves and their opponents, often sitting next to coaches while they pick things apart. Game plans become gospel. Revision of structures, set-ups and zones is paramount.

So when James Hird told emerging defender Jake Carlisle over summer he should go away and study vision of North Melbourne champion Wayne Carey, Carlisle got the sense more responsibility could be thrust his way in 2013, his fourth AFL season.

Carlisle spent most of last year establishing himself in Essendon's defence. He tended to take the second or third tall forward of the opposition, and managed an impressive job of stopping them before an ankle injury ended his season after 18 promising games.

Hird's first pre-season advice to him was to get fit: "I had surgery and he just wanted me to get right and come back as if I hadn't missed anything," Carlisle told AFL.com.au this week.

"I was in the gym and I tried to put a bit of weight on, and got a bit stronger. And then I just wanted to do what they asked."

The coach's next suggestion was to do some homework.

"Hirdy said 'I want you to watch some vision on people like Wayne Carey back in the day' and opponents who are key forwards in other sides," the 21-year-old said.

I did a lot of that, and did a lot of research to have a look. I didn't expect to get the role taking on the number one forward."

But it's a role Carlisle has taken on, and flourished in.

It started in the NAB Cup, when he outpointed Richmond's Jack Riewoldt, and has continued since. His triumphs so far read like a roll call of the competition's best forwards: Taylor Walker, Mitch Clark, Matthew Pavlich, Travis Cloke and Tom Hawkins.

And in round four he broke even with St Kilda captain Nick Riewoldt, someone he had also spent a lot of time observing and learning off in his preparation for the season.  

"The game's changed since Wayne Carey played, but I also watched a fair bit on Nick Riewoldt and the way Nick runs. He's been in the game a lot longer and has done a lot more pre-seasons [than me]," he said.

"But that's where I want to get to as a backman, to be able to expose other forwards and run all day."

On Saturday at Etihad Stadium, Carlisle will line up on another champion in Brisbane Lions co-captain Jonathan Brown, an opportunity he hasn't had before, and another job central to his side's success.  

Carlisle's position sees him assume high importance to the Bombers. He's more than a stopper; he marks strongly, kicks accurately and wants the ball in his hands.

His appetite for getting better comes in different forms.

Carlisle is a sports nut, closely following the ice hockey in Canada and American basketball. He watches two or three games live a week and records the others, often learning a thing or two about their defensive patterns and attacking methods and seeing if they translate to AFL.

Rival clubs have also kept an eye on his development, evidenced by Greater Western Sydney making a bid for him at the end of 2011.

"I would never have thought of leaving but it's always nice to have someone else recognise you for what you do," the 34-gamer said.

"I don't know what kind of deal it was [in terms of length] but I knew they had a bit of interest and we knew that where I was I wasn't getting much of an opportunity in my second year.

"But then I did (he played the last seven games of 2011) and obviously I'm pretty happy with being at the club and playing with Essendon."

So obvious that he recently signed a two-year deal extending his stay until at least the end of 2015 despite the on-going supplements drama involving the Bombers.

Carlisle said the saga did play on his mind "a little bit early" in pushing back contract talks, but he knew where he wanted to stay.

"We were going to look to do [the contract] just before we played our first NAB Cup game. And obviously a few things happened so we let it go for the time being to see how everything played out. But [then] we were going to look to do it mid-year anyway, but obviously the quicker you get it done the better," he said.

Follow AFL website reporter Callum Twomey on Twitter at @AFL_CalTwomey