But while the 21-year-old may not be the most physically imposing of centres compared to some of the midfield juggernauts from the southern hemisphere, D'Arcy revealed he is deceptively powerful.
"I'm really looking forward to playing with Andrew. He's been absolutely brilliant for Ulster. He was taking them all on against Biarritz last month - it was 'come and stop me if you want to' running," said the Leinster back.
"We've seen that form in training over the last week. He's sharp and a very powerful guy. He doesn't look the biggest player but you underestimate him at your peril. I've had a fair bit of banter with him over the last 10 days.
"As a player he's very well-rounded. His main attribute is his power off the mark. He's a very strong guy and I want to make his job as easy as possible by creating lots of space."
Ireland coach Eddie O'Sullivan has been eager to blood Trimble during the November internationals and only chose not to use him last weekend because he felt New Zealand was too harsh a baptism.
Luckily then for Trimble that he was able to sit-out the 45-7 defeat by the All Blacks, a match which saw the Tri-Nations champions' supremely gifted backline score all the tries for the second time on tour.
It does not get too much easier behind the scrum on Saturday, however, as the Wallabies' backline bristles with attacking options.
D'Arcy believes they will pose different problems to the All Blacks, looking to create openings for their strike runners as opposed to trying to smash their way through midfield.
"The Australian backline is keeping that team in games. They have a really good mix of pace and power. The backs are the driving force behind the Wallabies," he said.
"It's probably not fair to compare Australia's backs with New Zealand's. The Wallabies have players who ghost around you while New Zealand have target men and guys who can go through you.
"It won't be any less physical - guys like Morgan Turinui and Lote Tuqiri are as big as they come. But Australia would rather put players through the hole rather than ask a player to make a hole."