THE BRISBANE Lions have no plans to protect young ruckman Billy Longer when he makes his AFL debut, with the 18-year-old set for a baptism of fire against dominant Fremantle big man Aaron Sandilands on Saturday.

Longer, the No. 8 pick at last year's NAB AFL Draft, was presented with his jumper by Lions assistant coach Mark Harvey at Patersons Stadium on Friday and trained strongly as he prepares to play as a support ruckman to Matthew Leuenberger.

The 201cm teenager has added almost 10kg to his athletic frame since being recruited with the Lions' first pick at last year's Draft and midfield coach Shane Woewodin said he would spend time opposed to Sandilands during Saturday's clash. 

"Absolutely, that's why he's come in to play," Woewodin said. "He'll play as a ruckman and compete against him.

"Billy's not a beanpole 18-year-old ruckman, he's put a lot of time and work in the gym and he's got a big frame about him.

"We've just got to get him to use it and compete against him (Sandilands) and make sure our midfielders are a chance.

"It's a good challenge - an All Australian ruckman against a first gamer."

Woewodin said Western Bulldogs recruit Ben Hudson, who has supported Leuenberger in the opening two rounds, was not injured and the Lions had simply decided Longer deserved an opportunity.

The Northern Knights recruit is expected to spend time in a tall forward line that will also include Jonathan Brown, who is playing his first game after a pre-season facial injury, and possibly Daniel Merrett, who trained forward on Friday.

While Brown returns and will play a full game, the Lions will be without Brownlow medallist Simon Black (hand), putting pressure on their young midfield.

Woewodin said Saturday's match was an opportunity for players like Jack Redden, Daniel Rich and Tom Rockliff, who will continue to play forward and midfield, to take on more responsibility.

"We've got a really up-and-coming midfield," he said. "Without Black in there, the maximum games is probably 60-70 around the whole group.

"So it's a good opportunity for our midfielders to share the load and get the numbers through there … we're up against another good midfield."

Fremantle will be strengthened by the return of key onballer David Mundy, who has not played since undergoing serious ankle surgery at the end of last season.

Clearance specialist Michael Barlow, meanwhile, is expected to play a full game after two matches as Fremantle's starting substitute.

"Certainly it's part of their strength, their ability to win the ball around congestion," Woewodin said of Fremantle's midfield.

"They've got a good balance with a bit of outside and inside work, so that's going to be a good contest."

Nathan Schmook is a reporter for AFL Media. Follow him on Twitter: @AFL_Nathan