It was just a speculative go at something the coaching staff may vaguely think about, given they have given him some very small stints in the ruck.
I actually think you are right, it would be great if you could teach players to be more aggressive, and maybe some players can find that within them, but like Michael Oher said when he was annoyed at how he was depicted in the movie " The Blind Side" as needing to be taught how to be aggressive:
“I’ve always had that fire and passion in me on the field. You can’t put aggression into a person. It’s impossible. Either you have that toughness and aggression, or you don’t.”