Cowboys young gun Heilum Luki is facing multiple weeks on the sideline following his facial fracture suffered during the Cowboys win over Penrith in round 16.
Luki will have additional scans in the coming days to determine a more precise return date, however, it's believed he could miss at least a month.
The second-rower was on the receiving end of an accidental elbow by Penrith forward Liam Henry during the interchange players kickoff return.
While this is a devastating blow for the already hot-and-cold Cowboys, Nanai will be a straight swap for the injured 22-year-old once he returns from origin duty.
The second row stocks at Cowboys are the least of their worries regardless with the side still having Jack Gosiewski Sam McIntyre and Kulikefu Finefeuiaki all competing for a spot in the side.
It does not get easier though, as North Queensland will be hoping Origin carries a heavy toll for the Rabbitohs stars Damien Cook and Cameron Murray before they face the red-hot side on Sunday.