Ospreys will have to start the new season without their winger Hanno Dirksen.
The 22-year-old has not yet fully recovered from knee surgery carried out in November 2012.
Although his cartilage operation went well, his recovery is taking longer than expected according to head physio Chris Towers.
He said: "Hanno is behind where we originally predicted he would be at this stage after suffering complications that were beyond our control and which now appear to be remedied.
"Due to those setbacks he is only just starting on the rehab process during the pre-season period.
"He is coping well but it will be a while yet until we will see him on the field training with the rest of the squad.
"We will update on an expected return time when appropriate."