The 48-cap New Zealander had been due to link with his new team-mates this week, but the tie-up has been put back after what the region describe as a ''routine delay in the immigration process''.
Elite performance director Andrew Hore said: ''An application for a work permit has been submitted through the appropriate channels and we must wait for the paperwork to be completed before Jerry is able to join the rest of the squad for pre-season training.
''It's a situation that is unfortunately out of our control, but it is one that we are used to through our prior experience of recruiting overseas players.
''We fully understand and appreciate the regulations that are in place.
"We just have to wait for due process to be completed.''