Griffiths and United have been awaiting Football Federation Australia's receipt of the International Transfer Clearance to be processed by the Saudi Arabian Football Federation.

The certificate allows the former Newcastle Jets midfielder to be cleared from Saudi club Al-Shabab and be part of the Reds' AFC Champions League squad but there were fears it may not arrive in time for final squad registration next week.

But the clearance now means Griffiths will be ready to go for Adelaide United's highly anticipated opening match of the competition against the Pohang Steelers at Hindmarsh Stadium on Wednesday, February 24.

Griffiths's green light is another major piece of the Reds' AFC Champions League puzzle - after signing Roar striker Sergio van Dijk for the campaign yesterday - as United prepare for their third appearance in the prestigious Asian league.