Back-up hooker McInerney arrived in South Africa this week to bolster the struggling Brumbies before their clash against the Pretoria Bulls at Loftus Versfeld on Saturday night.

The 23-year-old has a part-time supplementary contract with the Brumbies as injury cover and put his job in Sydney on hold when Josh Mann-Rea's season ended after tearing his hamstring off the bone.

That meant doing the six hour round trip from Canberra to Sydney every week, even though the glass was missing from one of his back windows.

"But I got it fixed eventually ... the drive's a lot smoother now," McInerney laughed.

"And my little car, it just keeps going. It doesn't complain at all so I know basically every bit of the road by now.

"I guess [going to South Africa] is a little bit of a reward for all of that. But I'm still very nervous about getting out there if I get the chance this week."

Former Australian under-20s duo McInerney and lock Darcy Swain have been called into the Brumbies' squad as reinforcements for daunting task of trying to topple the Bulls at home.

The injury and suspension hit Brumbies are struggling to regain confidence and momentum after losing their past five games in a row, including a 42-24 defeat in Johannesburg last weekend.

McInerney replaces Robbie Abel and will be the back-up rake to rookie Folau Faingaa, while Swain will come into selection contention after Rory Arnold was suspended and Rob Valetini injured his knee.

McInerney moved to Sydney earlier this year for a fresh start after fearing he had fallen off the Brumbies radar when the club recruited his former Australian junior teammate Faingaa.

But Mann-Rea's injury led to McInerney making his debut two months ago when he got two minutes of game time in the Brumbies' win against the Durban Sharks.

"I think I'm ready, you've got to back yourself," McInerney said.

"I'm a lot fitter and stronger now so there's no real excuse to not go out there and play some good footy. There's no reason why I can't handle that step up.

"I've never been to South Africa so it should be good. It's going to brutal, but I think we can match [the Bulls]. I got a little taste of it against the Sharks I felt the impact [of South African teams] then. I know you've got to be more physical [in Super Rugby]."

The same problems that have plagued the Brumbies season came back to haunt them against the Lions. They played well in patches, but couldn't breakaway to breathe some new life into their campaign.

Arnold has been suspended for three weeks, opening the door for Blake Enever to return to the starting XV in time to launch his bid for Wallabies selection.

Faingaa was left to shoulder the bulk of the hooker duties last week after Abel was ruled out before kick-off with a calf injury. The Brumbies had two hookers on tour, forcing prop Les Leuluaialii-Makin to play two minutes in the unfamiliar role.

Faingaa and McInerney will be bracing for the abrasive Bulls and a duel with South African rugby veteran Adriaan Strauss.

"Folau has played some good games this year ... he's a first year player and the difficult things is fronting up every week, especially as a hooker," said Brumbies coach Dan McKellar.

"He was outstanding against the Lions, his lineout was good and he had a phenomenal work rate."

SUPER RUGBY ROUND 15

Saturday: Pretoria Bulls v ACT Brumbies at Loftus Versfeld, 11.05pm. TV time: Live on Fox Sports.