Out of action: Gareth Delve
Gloucester's Wales number eight Gareth Delve will have surgery on July 9 to assess the damage to his Anterior Cruciate Ligament (ACL) and will miss the start of the season.
Delve will undergo his operation following consultation with specialist Andy Williams and will be out of action for a number of months.
The 25-year-old suffered damage to his left knee during Wales' summer tour to South Africa.
"Gareth is a tremendous individual and an outstanding player - someone we wanted to build around for the future," said Gloucester's Head Coach Dean Ryan.
"This injury is obviously a significant set-back to him and the club but I have no doubts he will be back in Gloucester colours next season. He has drive, determination and a willingness to succeed and I am sure that will come through in his recovery."
Delve made 20 appearances in all competitions for Gloucester last season following his summer move from Bath.
Meanwhile, flanker Akapusi Qera will see a specialist in London on Monday to determine the extent of his knee injury.