Wallabies back-rower Pete Samu has been ruled out of the Brumbies' Super Rugby semi-final due to a strained hamstring.
Samu scored two tries in the Brumbies' thumping quarter-final win over the Sharks on Saturday but didn't return after halftime.
The two-time Super Rugby winner with the Crusaders stayed in Canberra on Sunday while his teammates flew to Buenos AIres to face the Jaguares for a spot in the final.
Samu has stood tall this season in the absence of star flanker David Pocock and will almost certainly be picked to play at the World Cup in September.
"Pete's played such a big role in getting us to where we are," Brumbies coach Dan McKellar said.
"I know we've got a little bit of depth in the back row and someone will step up to do a job.
"But players want to be playing at this time of year and (Samu) deserves to be."
Samu has been replaced on tour by two-Test Wallabies player Blake Enever and will likely be replaced in the Brumbies' starting side by veteran Lachy McCaffrey.
Samu's omission means former Queensland Reds prop James Slipper is the only active Brumbies player with a title-winning experience.
The Jaguares have won 10 of their past 11 games.
The Brumbies have won seven straight but their most recent loss came against the Argentine side.
An eighth consecutive win would extend the Brumbies single-season club record and book their first trip to the final since 2014.
They could even host the decider for the first time since 2004 if they oust the Jaguares and the Hurricanes upset the Crusaders in Christchurch on Saturday.
"We have confidence, we have belief, we have a group of blokes who love playing footy together, who love wearing the jersey and representing our people," McKellar said.
"And when you have that, special things can happen. We're excited about next Friday night and what lies ahead."
Andy Muirhead, Murray Douglas and rookie prop Angus Wagner were also added to the touring party.
