Waratahs scrumhalf Jake Gordon has joined the Wallabies squad, while Will Genia will miss six weeks with a broken arm.
Gordon returned to Sydney on Monday, after playing with the Waratahs, and has linked up with the national squad to replace Genia, who came off in the 27th minute in Melbourne.
Genia went in for surgery on Sunday and it was confirmed in a statement today that his Super Rugby season is all but over, with the halfback to miss six weeks.
Nick Phipps is most likely to replace Genia in the starting lineup, with Brumbies haflback Joe Powell the other nine in the squad.
Asked on Monday morning, before the confirmation of Gordon's inclusion, Wallabies attack coach Stephen Larkham said they had faith in the other nines to step up.
"He's an integral part of the team, there's no doubt about that, he's part of our strategy group and he's had a very good combination there with the forward pack and the backline," he said.
"So he's definitely a big loss but in saying that, we've got really good experience in Nick Phipps, Joe Powell's been around the team now for the last 12 months and we'll have to bring someone else into the team now."
The Wallabies take on Ireland in Sydney on Saturday June 23, kicking off at 8:05pm AEST, LIVE on FOX SPORTS, Channel Ten and RUGBY.com.au RADIO.