Dave Rennie confident Noah Lolesio's future is bright despite missing out on Wallabies selection

Rennie instead turned to veteran James O'Connor to replace the injured Quade Cooper in the second Test against the Pumas.

The coach said it was O'Connor's experience that proved a key factor in selecting the Reds flyhalf over Lolesio.

It was a decision that left the Brumby disappointed but determined to fight his way back into the side.

"With Quade gone, no [Michael Hooper], no Allan (Alaalatoa), we're keen to get a bit of experience out there," Rennie said. "James is an important voice in and among that backline.

"He's prepared really well, he's excited to get a crack and keen to make the most of it.

"Noah was disappointed but we've communicated that well and the areas we want him to be better. He was disappointed with the third Test, but he's a good kid.

"I reckon he's going to be an excellent international 10, he's definitely working hard on growing his game."

O'Connor leads a backline that has endured yet another unplanned reshuffle, with Lalakai Foketi into the starting side at inside centre after Hunter Paisami was ruled out with a concussion.

Departing Brumby Irae Simone was promoted to the bench, while Tom Wright retains his place at fullback. Rennie opted for Reece Hodge over Lolesio as the utility replacement.

At just 22 years old, Lolesio is still in the formative stages of his career.

While his performances at Super Rugby level for the Brumbies over the past three seasons have been outstanding, he has endured a tougher run at Test level.

Lolesio was superb against France last year, but struggled in the series decider against England at the Sydney Cricket Ground last month.

Rennie has been careful in his development of the emerging playmaker as he looks to turn the youngster into the Wallabies' long-term flyhalf.

"We've talked about connection, it's a strength of his game at the Brumbies," Rennie said. "He probably wasn't as sharp (against England), he got deeper and deeper as the game went on to buy himself some time.

"He's the type of player who probably doesn't have the leg speed of a Beauden Barrett so he needs to be able to play flat but still get himself into a position where he can run, kick, pass. They are areas we want him to be better in.

"He's played around a dozen Tests now, they were all against top teams, a number against the French, the English, South Africa. He's played big games and will be better for that."

The decision to select O'Connor comes as concerns have been raised about flyhalf depth in Australian rugby.

At 34 and 32 respectively, Cooper and O'Connor are approaching the end of their playing days. The 22-year-old Lolesio is only in the formative stage of his career.

There are few playmakers in the middle.

Reece Hodge stepped into flyhalf last weekend, but the 27-year-old has been viewed more as a utility rather than a front-line flyhalf option.

Rennie concedes it's an area of concern for Australian rugby and he's focused on ensuring Lolesio leads through a talented crop of playmakers that includes Tane Edmed, Ben Donaldson and Will Harrison.

"It's something we're talking about," Rennie said. "We've got a few plans and we've got some good young kids coming through but they're not ready for this level yet. We get home and we've got South Africa and the All Blacks, the two best sides in the world.

"It's an area of focus, we need to accelerate the development of our young 10s."