IF YOU are a key defender, they are the two biggest tasks in footy.

West Coast and Richmond, Josh Kennedy and Tom Lynch.

At Carlton, Jacob Weitering has spent his last fortnight preparing meticulously for both.

Now in his fourth year at the Blues, the former No.1 pick has overcome a difficult period adjusting to the challenges and rigours of senior footy. Those struggles reached a tipping point last season, when he was sent back to the VFL to re-find confidence and form.

Weitering spent time in the VFL last season. 

It was a period that shaped Weitering, who has become one of the club's most consistent performers down back amid its sudden return to winning ways under caretaker coach David Teague.

The 21-year-old changed his mindset, tweaked his training habits and worked hard on his defensive craft, resulting in him starting to become the player he showed he could be throughout a gifted junior career.

His 51 intercept marks this year are the sixth most in the League, while his 111 spoils has him ranked inside the top 10 in the competition in another significant defensive category.

Weitering has since been recognised for that consistency, one of five Carlton players – along with Harry McKay, Sam Walsh, Sam Petrevski-Seton and Zac Fisher – to be named in the AFL Players' Association's 40-man '22under22' squad that was revealed on Wednesday.

>> Full 40-man 22under22 below

An improving, solid partnership with Liam Jones has also helped his form.

If quelling Kennedy and Lynch wasn't tough enough, the Blues also have to limit the influence of their partners in crime: Jack Darling and Jack Riewoldt.

In the absence of the unavailable Jones, Blues rookie Hugh Goddard was handed the role of stopping Darling last week. Jones could return this Sunday to take on Riewoldt.

Goddard played his second match of the season last week against West Coast.

So, how do you prepare for such a challenge?

"Firstly, you'll look at the team you're playing," Weitering told AFL.com.au.

"The way they move the ball, the way they defend and who they move the ball through.

"I go back to watching vision, which my line coach (Dale Amos) helps me a lot with. We'll watch the previous three or four weeks, watching where and when they got their marks.

"We'll watch all of the inside 50s that the team gets, looking at patterns and trying to put a plan in place to stop them. You can't stop everything – I wish you could, but you can't – so you just try to nullify their strengths and works to yours.

"For me, I'll be doing the same this week. That's another thing that 'Jonesy' does better than anyone, his preparation. I like to think I can keep it all in my head, but he's got his notebook. It's got pages and pages worth of knowledge on how to face players.

"He's had some great days on players like Buddy Franklin, learning from games like the one a couple of years ago when Buddy really got a hold of us."

Weitering and Jones have provided the foundation for a developing young Carlton backline that is conceding nearly 20 points per game less than it was last season.

Weitering and Jones have formed a formidable duo. 

But while they are gaining more chemistry within their relationship on the field, it is being built on the back of a strong and motivating friendship away from footy.

"He's one of the nicest guys," Weitering said of his defensive teammate.

"The way he revived his career … he'd say it himself, he was probably gone. He was off the list, delisted … he was probably thinking the most negative out of anyone.

"But the way he turned himself around … he went down back and just started dominating in the VFL. He just wanted to earn respect and give everyone a look at how he never gives up.

"He's an effort-based player and you can see that from the way he attacks the ball. He's got a lot of respect from me and his teammates. He gives back a lot as well.

"When I was going through those tough times, he was more than happy for me to ask questions and help me with craft training."

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Carlton's defenders – and Weitering, in particular – used last week's clash with West Coast as a chance to measure themselves against the game's best forward line.

For Weitering, the first test was passed. He limited Kennedy to just five disposals, three marks and only one goal throughout the afternoon. All of that after the two-time Coleman Medal winner had torched North Melbourne with seven goals the previous week.

He'll do the same against Richmond at the MCG on Sunday.

"For me and Jonesy, it's a great challenge," Weitering said.

"We'll take that with both hands because that's what we pride ourselves on.

"To be the best, you've got to beat the best. I know it sounds like a cliché, but we both like the challenge of playing on the bigger players.

"I'm only 21, but at some point, I'll have to take the No.1 role every week. That's exciting."