Australia centre Rob Horne is facing a lengthy spell on the sidelines after he underwent elbow surgery.
The 21-year-old Waratah had impressed during the Tri-Nations Series - but his season was brought to an end after he damaged his right elbow against New Zealand in July.
And although Horne returned to pre-season training with the Tahs, he has now faces missing all of the Super 15 season.
Tahs coach Chris Hickey said: "It was a fairly serious injury and unusual surgery that needed to be done.
"The medical advice is that he could be right by February but it could take until June.
"It's one of those things that we're not really going to know until February."