Wallabies back James O'Connor is set to miss 1-2 weeks after damaging his left sternoclavicular joint on Saturday.
Although scans have confirmed no fracture, Australia's playmaker is a doubt for the Rebels' clash with the Stormers on Friday at AAMI Park.
O'Connor was injured in the early stages of the Rebels loss to the Blues and was unable to continue, after initially playing through the injury.
The Rebels will also be without rookie, and O'Connor's replacement, Angus Roberts, who departed the action with a dislocated shoulder.
Roberts will be further assessed on Monday, with surgeons to determine the full extent of the damage and if any further action will be required.