The Brumbies have been forced into a late reshuffle for Friday's crucial Super Rugby match against the Melbourne Rebels, with injury further decimating their backline.
Robbie Coleman was on Thursday ruled out of clash at AAMI Park with a hamstring complaint stemming from last week's home win over the Bulls.
Coleman had been named at inside centre in place of Wallabies star Matt Toomua, who is sidelined for at least a month with a knee surgery.
His withdrawal means winger James Dargaville will shift to No.12, with Lausii Taliauli promoted to the starting side - for the first time in 2016 - on the wing.
Rookie Jordan Jackson-Hope, who played in Australia's under-20s team against New Zealand last week, will take Taliauli's spot on the bench and is a chance to make his Super Rugby debut.
While it will be Dargaville's first start at inside centre for the Brumbies, the 24-year-old played the majority of his junior and representative rugby in that position.
"It's not ideal losing a player like Robbie," coach Stephen Larkham said on Thursday.
"He's been very good over the last couple of weeks, bringing energy to the side and experience into the team but it gives an opportunity to Jordan Jackson-Hope who's trained with us pre-Christmas."
Injury has plagued the club this season, with Coleman joining Toomua and Wallabies wingers Joe Tomane (knee) and Henry Speight (cheekbone) in the casualty ward.
Yet they've managed to regain the Australian conference lead in a tight battle with the Rebels and NSW Waratahs for one guaranteed finals berth.
"I think the beauty of this team and this organisation is that we've been able to adapt really well to situations on and off the field," said Larkham.
"Having Christian (Lealiifano) as our five-eighth, our playmaker, as our captain out there, he's one of the best at adapting and making situations work."
The Brumbies, equal on points with the Tahs and two ahead of the Rebels, have lost their last two games against their Melbourne rivals.
Larkham said their breakdown was a danger with Colby Fainga'a and Sean McMahon in the backrow.
"They'll be pretty hard on the ball and that's where they stifle teams, so that'll be a real focus for us," he added.
"Every game from now on is important for us. We're in that situation where we've got to pretty much each week but our focus won't be too far ahead."