New recruits Matt Giteau and Rocky Elsom both have been cleared to play after missing the season-opener through injury.

This is a  major boost for the Brumbies ahead of Sunday's Super 14 clash against the defending champion Bulls.

Giteau (quadriceps) and Elsom (hamstring) have both been rushed straight into the starting line-up despite not having played a trial match for the Canberra-based club.

Elsom's debut appearance in Brumbies colours sees Mitch Chapman drop back to the bench, while 19-year-old prospect Matt Toomua makes way for Giteau who will start in his preferred position of fly-half.

In the only other change to the Brumbies' starting line-up from last weekend's opening 25-14 win over the Western Force in Perth, tighthead prop Salesi Ma'afu replaces Guy Shepherdson in the front row.

Brumbies coach Andy Friend welcomed the return of Elsom and Giteau against a red-hot Bulls line-up in Pretoria.

"The Bulls at Loftus Versfeld presents a significant challenge for any side in the competition," Friend said.

"There's an appreciation within the side that we need to step up from where we finished last week and we've identified where we need to improve against a quality Bulls outfit.

"We certainly need to be more physical in the contest and I think Rocky will help us achieve that.

"In saying that, Mitch was one of our hardest working forwards in the Force game but given Rocky's returning from an injury, it made sense to put him straight into the game after the warm-up without giving him a chance to cool down on the bench.

"Matt will also bring further class to our back line. It's a tough call for Matty Toomua who's been excellent for us this year and he's formed a great combination with Christian (Lealiifano) at 12, but Gits is a world-class player that you can't leave out of your side."