Glenn admits the highly touted rookie forward will need some soothing words before he runs out against Melbourne at AAMI Park in this week's season opener.

But he didn't sound confident of achieving much on Friday, predicting 19-year-old Flegler would unleash the beast against the Storm.

"This is my 10th season so I will give him some tips on how to control his nerves and what he needs to do out there," Glenn said.

"(But) there's something about him; when he crosses that white line, he just goes into animal mode."

Not that Glenn was complaining.

He believes the 190cm, 108kg teenager is just what Brisbane needs lining up against a monster Storm pack boasting Nelson Asofa-Solomona and Jesse Bromwich.

"He's a weapon. His impact when he came on the field in the trials was great and that is what we need," Glenn told Broncos website.

"He's got aggression in defence and runs hard. It will be good to unleash him down there.

"I am sure he will handle it well and what better test than going up against a quality pack like the Storm."

Flegler is assured of making his NRL debut after coach Anthony Seibold surprised club faithful at the Broncos' season launch last Friday by unveiling his 18-strong squad.

He's on the bench with David Fifita, who was beaten to a starting back-row spot alongside Glenn by fellow young gun Jaydn Su'A.

Tevita Pangai is also on the interchange as he returns from a hamstring complaint with Matt Gillett in the unfamiliar position of lock.

Gillett had no doubt Flegler was ready to be blooded against Melbourne after three impressive trials.

"You know what you are going to get out of Fleggie," Gillett said.

"He has got one speed and that is 100 miles an hour.

"He has played every trial and there is a reason for that. He is a big fella and pretty aggressive.

"When he gets his time to play he is not going to let the lads down."

Australian Associated Press