If Mealamu is sidelined on Friday, his absence should be balanced by the return of All Black loosehead prop Tony Woodcock.
He has been on leave, but after playing 103 games for the franchise since his debut a decade ago against the Hurricanes, he is due to resume against the same opposition.
He played for the Blues development side last week against the Fiji Warriors, and while not yet fully fit he proclaimed himself ready for a return to the Super 15.
The Blues are also sweating on a verdict for flanker Luke Braid, who was cited for foul play in the team's defeat by the Stormers in Cape Town.
There is some optimism that Rudi Wulf has recovered from his shoulder complaint and could return at fullback for the injured Isaia Toeava or on the wing for the suspended Rene Ranger. First-year pick David Raikuna missed the last game with a hamstring strain but may also be fit enough to play on Friday.
Five-eighths Gareth Anscombe, who started both matches in South Africa, broke his nose in the game against the Stormers but will start. He will be needed with Michael Hobbs on bereavement leave and utility Piri Weepu still appearing short of match fitness.
The damage list does not stop there. All Black lock Anthony Boric is recovering from a neck injury while Toeava is waiting for further assessment of a recurring hip injury - injuries which flared up in South Africa and forced the pair to fly home early.
They were joined by outside back Ranger, who is serving a two-game ban for an illegal tackle, while another outside back, George Moala, is still recuperating from a shoulder problem.