Kerr-Barlow struggled after a head-knock in Argentina and has been spelled for the Chiefs since, while Perenara's decisions do not keep pace with his fitness levels.
In the last round Weber was not in the same gnarly form as some of his teammates but he matched up against one-time All Black Alby Mathewson and gets a repeat chance against the Brumbies.
They have picked up former Pumas halfback Tomas Cubelli who has 45 caps and is a strong replacement in their squad for occasional Wallaby Nic White.
Cubelli impressed coach Stephen Larkham so much he labelled him the "best running halfback in Brumbies history" - an assessment sure to provoke lively conversation between the coach and former teammate George Gregan.
"He's very clever around the rucks and he's got that little bit of Argentinian flair where he only needs a sniff of a space and he can get through it - and he's got all the skills to back it up," Larkham added.
Those comments have set the scene for Weber and the Chiefs to make sure their A game is in order for their visit to Canberra.
Weber has an all-purpose game which is the closest to the Smith template, buffed through his 47 All Black tests. His kicking can vary but Weber's pass is rapid and usually on the mark, he has terrific speed to break or back up teammates and is a resolute defender.
His choices seem balanced, which is a sign of someone who scans the field and is combining well with players like Michael Leitch and Aaron Cruden around him.
Matchups against other NZ halfback hopefuls will carry great weight with the selectors but this duel with Cubelli and Co will also be one to absorb.
