Wallabies and Rebels flyhalf James O'Connor is in danger of missing the British and Irish Lions tour of Australia due to injury.
O'Connor was injured playing for his team the Rebels against the Blues in Auckland and took a knock in the chest.
The 22-year-old played on after the initial knock after receiving treatment but then suffered an even bigger knock when he collided with former All Black Rene Ranger.
O'Connor can play at fly-half, wing or full-back is one of Australia's best players but missed much of last season due to injury.
O'Connor left the field after 26 minutes and almost immediately tweeted,"Painful stuff! Popped my sternum out on that kick receipt then didn't help when I got back up and had ranger with a 40m run up coming at me..."
The back went for an MRI scan and said on his Twitter account,"On way to MRI and X-ray scans now, hopefully nothing internal again."
After he had the MRI scan he revealed that he would need further scans to confirm the damage but said that nothing was broken.
"Initial scans looking ok- nothing broken or internally damaged. Couple more scans tomorrow to tell full extent.. Feeling more positive tho", said O'Connor on Twitter.
Wallabies coach Robbie Deans is expected to name a 25-man training squad next week and a further six players will be added on the 11th of June.
Quade Cooper has so far been left out of the Wallabies training squad but has been the most impressive of the Australian number 10's in Super Rugby and is also the most familiar with Will Genia.
O'Connor's Rebels team mate Kurtley Beale could also play at 10 for the Wallabies but was stood down by his team on the weekend for a second breach of discipline having been allowed to return to the team just last week.
Beale could still face a sanction from the Australian Rugby Union, but Deans has insisted that Beale would be considered for selection.