Wade Graham's regular season comeback from concussions has been delayed with the Cronulla captain requiring ankle surgery.
Graham was injured in the early stages of Monday night's NRL trial win over Canterbury, limping off in his first game since last June.
The back-rower was upbeat on Tuesday that he could still potentially play round one but scans have now confirmed a syndesmosis injury to his left ankle.
Graham will now miss up to six weeks, ruling him out of the first month of the season with his earliest possible return against Wests Tigers in round five.
The 31-year-old's injury comes at the end of a tough pre-season for new Sharks coach Craig Fitzgibbon, with Cameron McInnes also sidelined for the opening month.
The news on Graham came as he declared he was confident he had put concussion issues behind him.
"It's frustrating because I was ready to go," Graham told AAP.
"I haven't missed a beat this pre-season. I have put in a really good training block.
"So to get out there and just get caught in an innocuous way is frustrating.
"But it is what it is. I am confident in the work I have done."
