Flyhalf Matt Toomua will join the Brumbies ahead of Saturday's clash with the Lions at Ellis Park.

Toomua has missed the past four weeks due to an ankle injury, but will arrive in Johannesburg on Tuesday as the Brumbies look to bounce back from their narrow defeat to the Stormers at the weekend.

The result in Cape Town means the Brumbies have now lost four of their last five matches and they'll need a result in Johannesburg if they hope to keep hold of the top spot in the Australian conference.

The Brumbies might've been on the other side of the result had Toomua's replacement at flyhalf, Christian Lealiifano, been successful with his conversion attempt following David Pocock's try.

Five of the Brumbies' six losses this season have come within seven points or less and coach Stephen Larkham is hoping they can turn that around at Ellis Park.

'You've got to stay with it; had those tight games gone the other way we're on 49 points on the ladder,' he told the Canberra Times. 'We know we're almost there. You change a few things but don't make wholesale changes.

'It's definitely a frustrating season, we're lucky to be on top of the Australian conference. We've said “what if”. But the season's not over.

'We'll look back at moments that could have turned the season for us.'

Photo: Hannah Peters/Getty Images