Koloamatangi left the field late after copping a high hit in the Rabbitohs' loss to Canterbury on Sunday night.
He subsequently passed his concussion test, but Souths staff fear he may have suffered bone damage and the forward therefore won't fly to Perth as planned.
NSW officials have since confirmed Koloamatangi has been ruled out of the Blues' squad, with Canterbury second-rower Jacob Preston brought in.Â
Koloamatangi had only been listed as 19th man after losing out to Stefano Utoikamanu in the race to replace the injured Mitch Barnett.
It means he only would have featured in Wednesday night's game if the Blues suffered an injury in the final two days of preparation.
NSW have already lost Haumole Olakau'atu as a reserve for game two, after he requested not to fly west with his partner due to give birth.
The Manly second-rower then suffered a shoulder dislocation in the Sea Eagles' loss to Gold Coast on Friday night.
The Blues already have Penrith prop Lindsay Smith in their 20-man squad as cover.
It was initially thought he would fly back to Sydney on Tuesday in order to play for Penrith in Auckland on Saturday, but that is now likely to be delayed.
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