KEEPING Geelong's Tom Hawkins goalless doesn't happen often these days.

 

Since his breakout finals series in 2011, the young star has gone without a goal just five times.

 

But when Richmond's David Astbury did it in round seven, hardly anyone noticed.

 

That's not a big surprise because key defenders are about as hip as a hip operation.

 

But considering only defenders from the Sydney Swans, Fremantle, Hawthorn and Adelaide (in 2012) have also kept Hawkins' goalless in that period, Astbury's performance has merit.

 

To add weight to his efforts, Astbury has also held Travis Cloke and Charlie Dixon goalless and quelled Jarryd Roughead in the first seven rounds.

 

Only an old grumpy Lion called Jonathan Brown took on the young Tiger and won, kicking four goals in their duel in round five.

 

Astbury's not alone in showing this season he has what it takes to be a long-term key defender of quality.

 

Melbourne's Tom McDonald, Collingwood's Jack Frost, Gold Coast's Steven May, Port Adelaide's Jack Hombsch and Essendon's Cale Hooker make up a back six with a difference.

 

All are emerging defenders with – apart from Hooker – fewer than 50 games experience who are putting together performances to make people stand up and take notice.

 

Hooker has more experience (95 games) but he sits among this lot because even his coach Mark Thompson admitted he's taken his game to a level he never expected him to this year. Hooker has conceded just five goals and leads the competition for intercept marks. 

 

By contrast to Hooker, McDonald has been promising since he emerged under enormous pressure in 2012 to finish third in the club's best and fairest and earn a Rising Star nomination.

 

He has taken another step this season. He is much more measured in his decision-making than he was in the past because he now runs off his opponents with a plan more often than not.

 

Melbourne's defensive coach Jade Rawlings told AFL.com.au a key defender such as McDonald is worth their weight in gold.

 

According to Rawlings, McDonald has the quality all good defenders need: elite mental fitness.

 

"He has to concentrate," Rawlings said. "We ask a lot of him as far as his opponents and also minutes played on the ground and he is an elite endurance athlete."

 

This season, McDonald, 21, has played on Nick Riewoldt (who kicked three on McDonald when the Demon suffered a bad corkie), Jack Darling, Jeremy Cameron, Lachie Henderson, Tom Lynch, Lance Franklin, James Podsiadly and Liam Jones. Only Riewoldt managed more than two goals.

 

Rawlings said the most difficult thing to coach defenders is their positioning.

 

"[It's about] understanding where the ball is and where you need to be: is it space or is it body? All that can change depending on who your opponent is," Rawlings said.

 

Such defenders don't cost the earth at the NAB AFL Draft either.

 

May and Hombsch were accessed through talent acquisition concessions granted to the expansion clubs. Port Adelaide then traded pick 28 for Hombsch, while Astbury was pick No.35, McDonald (No.53), Hooker (No.54) and Frost a rookie. 

 

Perhaps it explains why May and Hombsch are more creative than the other four – Hombsch has launched scores on 11 occasions and May 10 times in 2014 – but it also reflects that fact they are playing in winning teams.

 

In the early stages of their careers and with many yet to play in finals, these are such names – along with Carlton's Simon White and Sam Rowe and the Bulldogs' Jordan Roughead – are pushing to become the Tom Lonergan type of the next generation.

 

"[McDonald] has had to learn on the job, which is one of the most beneficial things for a young key back," Rawlings said.