Brumbies backrower Jarrad Butler is set for a month-long absence with a medial injury,.
Butler was a late withdrawal from the Brumbies side to face the Stormers in Cape Town, replaced by Jordan Smiler in the starting XV.
The 24-year-old twisted his knee in training earlier, with scans revealing the extent of the damage.
Brumbies coach Stephen Larkham said Butler would head back to Australia following the Stormers match, with at east four weeks out of Super Rugby.
“Jarrad has been in great form this season,” he said.
“He was going through some drills at training and twisted his knee.
"We gave him every chance to recover in time for the Stormers match but the scans have revealed damage to the medial ligament.
“Jarrad will be with the team tonight before flying home to continue his rehabilitation and we hope to have him back playing in around four weeks.”
The 24-year-old has been one of the standouts for the Brumbies so far this season, earning a starting opportunity after an injury to Ita Vaea.
Butler was replaced by Jordan Smiler in the starting XV, with former Australian Sevens representative Michael Wells coming on to the bench for the first time.