At 201cm and 103kg, teenager Billy Longer knows all about filling big shoes.

But that won’t make his task at the Brisbane Lions any easier.

With just one AFL game under his belt, Longer must step up in the long term absence of ruckman Matthew Leuenberger (Achilles) – starting with Saturday night’s derby clash with the Gold Coast Suns.

And all at the tender age of 18.

It’s a tall order – but Longer is backing himself after a brutal AFL introduction.

The No.8 draft pick was not cut any slack on debut, lining up against Fremantle big man Aaron Sandilands last weekend.

An understated Longer described it as a “different” experience that had steeled him for the task ahead.

“I was bruised and battered but I do enjoy that side of football,” he said.

“It’s part of the game. And you can’t help but learn from someone like that (Sandilands).”

Longer stood tall in the absence of Leuenberger, who was subbed off early in the 29-point loss to Fremantle before being ruled out for at least six weeks.

Longer was not sure what was more painful – taking on Sandilands or watching his mentor Leuenberger limp off.

“It is a huge disappointment for him and us. He’s been one of my mentors since I have been here so it is upsetting to see him go down the way he did,” Longer said on Tuesday.

“Leuey has been an amazing teammate.

“He’s helped me a lot in my growth as a footballer.

“We spend a lot of time together outside of football.

“As sad as it is for Leuey I want to make the most of this opportunity – these next few weeks I will try to get the most out of it as I can.”

Leuenberger has battled Achilles tendonitis for months – not that it helped Longer digest news of his good mate’s lengthy layoff.

“Speaking to him today he said it was going to happen at some stage – it’s been giving him some trouble for a while,” Longer said.

“It was a case of holding your breath and waiting for it to happen – sadly it did.

“The strength and conditioning staff managed it fairly well but there are some things that are just going to happen.”

Longer will combine with veteran ex-Western Bulldog Ben Hudson in Leuenberger’s absence.

His first task will be fellow young gun – the Gold Coast’s 205cm Zac Smith – in what promises to be an absorbing duel at the Gabba on Saturday night.

But Longer – who has incredibly added 10kg to his frame since being drafted – said Leuenberger would still be a factor for the Lions despite being injured.

“Leuey will still be there giving us pointers and helping us however he can from the sidelines,” he said.