Cardiff's former All Blacks number eight Xavier Rush will be out of action for up to three months after damaging his knee in training.

The 31-year-old tore the cartilage from the back of his knee cap and will undergo surgery this Wednesday, meaning he will miss the start of Blues' new campaign.

"I injured the knee in training - however we won't know the full extent of the injury until I see the surgeon," Rush said. "It's likely that I will need and operation to fix the problem which would put me out for up to 12 weeks which would be disappointing."