Suliasi Vunivalu is likely to debut in Sydney's deciding third Test after a host of Wallabies injuries in a loss to England, headlined by Izaia Perese's knee.

Veteran James Slipper admits things "might get interesting" as the injury-whacked Wallabies attempt to plug more gaps for Sydney's deciding third Test against England.

Reinforcements may need to be called in for Saturday's clash after a serious knee injury for Izaia Perese headlined the carnage in Brisbane.

Scans will confirm if the utility back tore his ACL in Saturday night's 25-17 loss at Suncorp Stadium.

Lock Cadeyrn Neville also suffered a knee injury, fullback Jordan Petaia was concussed in the third minute and Scott Sio (arm, shoulder) lasted no longer when he came on in the second half.

Allan Alaalatoa (concussion) and centre Len Ikitau (calf) should both be fit to play at the SCG on Saturday at least.

But with Jed Holloway, Quade Cooper, Tom Banks and Andrew Kellaway already in the casualty ward and Darcy Swain suspended for another Test the cupboard is almost bare.

The Wallabies remain particularly thin in the second row and at fullback, with Reece Hodge flown into the squad as cover and now a potential fix in the No.15 and lock Nick Frost a chance to start after debuting off the bench.

Backrowers Harry Wilson and Ned Hanigan could come in if Dave Rennie shuffles the deck, while the coach said he'd consider adding a specialist second-rower to the squad once a clearer picture of their injury toll was possible on Sunday.

"I may as well just go second row next week," prop Slipper smiled.

"It's obviously a test ... certain positions are challenging at the moment. We're pretty blessed in the outside back area. The second row could be interesting.

"I won't say I'm stressed about it at all; next man up, let's roll, big game."

Perese and Petaia's exits pave the way for code-hopper Suliasi Vunivalu's much-hyped debut on a wing or off the bench, the former NRL premiership winner training strongly with the squad after a series of hamstring injuries since returning to rugby.

Petaia's early departure was a headache for a side searching for a fullback ahead of next year's World Cup, Kellaway strong when moved there in Perth but now facing up to eight weeks on the sideline.

Petaia stumbled to his feet after a tackle gone wrong and would appear long odds to feature in Sydney in another setback for the talented 22-year-old.

Slipper won't use the injuries as an excuse though, given his team came from 19-0 down to threaten an upset in Brisbane.

"We were in a position to win that game with 10 minutes to go," Slipper said.

"By playing at the wrong end of the field ... not winning the kicking game, set piece under pressure, that was pretty good to be in that position.

"But in Test matches you need to win the contact area, it's pretty hard when you're always going backwards.

"It sets up a pretty big game in Sydney. There will be a lot on the line and what a spot to do it at."

Australia scored two tries to one but Owen Farrell's six penalties and a conversion from eight attempts were the difference behind a dominant pack.

"We knew it (the physicality) was coming, we just didn't tackle well enough ... and we have to look at our discipline," Rennie said.