Rebels flank Scott Higginbotham is in doubt for their clash at the Cheetahs, with the back-row forward struggling to overcome a shoulder injury.
Higginbotham left the field for the Rebels after a try in the 68th minute during the franchise's heavy loss to the Sharks in Durban on Saturday.
"Scott will have an MRI today, South African morning time, to assess the nature of the injury," read a statement.
"This is a separate incident from the injury he sustained against Wales on the Wallabies Spring Tour in 2012."
Rebels coach Damien Hill said Higginbotham would be given every chance to prove his fitness.
"We are fortunate to have great depth in this position. Jordy Reid has been impressive in his limited game time and with Jarrod Saffy travelling with the squad," he explained.
"This is a huge game for this group of Rebels players and knowing Scott, he will be desperate to play and will be given every chance."