Hunt, 26, was a late inclusion into the national squad after Rooke fell ill during a recent trip to Bali.
The hospitalisation of Rooke last week meant the premiership midfielder couldn't take his place in the side that faced off with the Irish in the first Test of the Toyota International Rules series last Friday at Subiaco.
And so Hunt was called shortly before the game to see if he'd like to take Rooke's spot in the squad for the second match.
The defender, who said he was delighted to be given the chance to play for his country, admitted that coming in at the expense of his fellow Cat was difficult.
"To have to come in under those circumstances, to replace a teammate and a guy I love when I know how much it would have meant to him to play, has been hard," he told afl.com.au after Australia's final training session on Thursday.
"It's not a great thing to take Rooke's spot, but at the end of the day, there wasn't much choice.
"I think he'd prefer it to be one of his teammates if he had to be replaced. But Rookie is not forgotten around here; all the boys love him and ask how he's going.
"He leaves an impression on anyone; he's a great bloke."
Hunt said he would try to speak to Rooke, who is resting at home, before the match on Friday. There is even a remote possibility Rooke will be at the MCG showdown after overcoming the worst of his illness.
Meanwhile Hunt is still getting used to the fact he's in the representative squad – and now the final side after Scott Thompson withdrew with a calf injury on Thursday.
He's also had just three days to adapt to the round ball and the other specific IR skills required.
"I'm a bit behind the eight-ball kicking-wise, and the skills are hard to get used to. It's the first time I've ever had to do it," he said.
"It's so different from the oval ball. I've gotten better in three days, but you have to get used to the fact you can't kick it as hard as you can kick the footy.
"You've got to kick the outside of the ball to get that spin on it and to make it bend. They're a lot less forgiving than our footies."
While his national teammates were warming down on Thursday, Hunt was pulled aside to watch a short DVD on the rules of the game after missing the team's meeting with the umpires last week.
"It helps a lot. After watching the little bit that I did last week it was sort of a bit of a blur really, some of the rules, but now it's a lot more clear cut," he said.
"It's similar to our game, and obviously has some rules that are similar to theirs, but it's easy to get used to.
"I got the gist of it. It's a pretty quick game."
Hunt is hoping to fill a role on the back line after possibly starting on the bench. But he was keen to shy away from the poisoned chalice of goalkeeper, a position both Nathan Bock and Michael Firrito have been less than enthusiastic to hold.
"I'm not [putting my hand up for 'keeper] after seeing Spud out there, no. They come in pretty quick from that penalty spot, and it's a daunting task," he laughed.
"Anyone who takes that on is a very brave man.
"But, it's going to be a bit of an adventure out there on Friday night. I'm looking forward to it."
