Wallabies and Rebels winger Cooper Vuna is in doubt for the rest of the Super Rugby season after he suffered a suspected shoulder fracture in the Rebels loss to the Waratahs.
Wallaby winger Vuna left the field in the 18th minute of the 24-16 loss at North Hobart Oval holding his shoulder.
The injury was initially thought to be just a "stinger" but a Rebels official has now said that they will investigate whether it was a break.
The former Newcastle Knights rugby league back broke into the Wallabies team last season but his season was cut short when he dislocated his left shoulder playing club rugby.
Vuna had surgery on the shoulder last year.
Melbourne Rebels assistant coach John Muggleton said that the two doctors that were traveling with the side would assess Vuna before deciding whether xrays in Hobart were necessary.
"It's a bit of a funny one," Muggleton said.
"We're not sure what's wrong."
"He's sore behind the shoulder in the scapula area so obviously we'll just wait and see how it settles down and the doctors will make a decision on that."
On a positive note flyhalf James O'Connor made it through the trial unscathed which will boost his confidence after an injury-plagued 2012 season.
"The last three or four times he's played he's been injured so for him to get through that ... was good for his mental approach," Muggleton told AAP of O'Connor.
The Rebels have another warm up match next weekend against the Hurricanes in Geelong and Wallabies star Kurtley Beale is expected to play.