Josh Mann-Rea and David Pocock will both be heading home early from the Brumbies' South Africa-Argentina tour in a double injury blow for the side.
Mann-Rea limped off the field midway through the second half of the Brumbies' win over the Stormers in Cape Town and has reportedly suffered a suspected ACL injury.
The hooker is the oldest player in Super Rugby at the moment and a long layoff could potentially spell the end of his career.
Pocock is still struggling with a calf injury that he picked up in a January preseason camp with the Wallabies.
He hasn't played since aggravating the issue on March 8 after already having a delayed start to the season because of the injury.
Brumbies coach Dan McKellar was confident as late as last Thursday that Pocock would be fit for their round 11 clash with the Jaguares but that prospect has been dashed already.
McKellar said last week that Pocock's time out had been frustrating for both the player and the side.
"It all started back in January at the Wallabies camp and hasn’t stopped really,” he said.
"If I had have been told, when I was originally told it was a calf strain in January, that it would be still dragging on in the back end of April, you’d certainly be frustrated.
"He’s been frustrated, as much as anyone. He works hard on his rehab and wants to contribute to the team. He still certainly had a really good contribution but he wants to be able to have a contribution on the field and hasn’t been able to do that this year.
"But there is still a long way to go and it’ll be nice to have him back for the second part of the season.
"We have to make sure if we throw him back into a game situation that he is prepared and ready to perform. And not just play, so the last thing we want him to do is have another set back.”
The form of Locky McCaffrey has somewhat offset Pocock's absence and though he missed the Stormers match, the gritty no. 8 is expected to return in Buenos Aires.
Rookie flanker Jahrome Brown was also impressive in his run-on debut in Cape Town while Tom Cusack has been consistent when he has had opportunities in the no. 7 jersey this season.
Connal McInerney will link up with the Brumbies in Argentina to replace Mann-Rea.
The Brumbies take on the Jaguares in Buenos Aires on Saturday April 27, Sunday April 28 at 7:40am AEST, LIVE on FOX SPORTS and Kayo Sports.