The Western Force are set to replace one Wallabies hooker with another for their Super Rugby Pacific clash with the Highlanders in Invercargill.
Folau Fainga'a is expected to enter the 12-day concussion protocols after copping a knock to the head in Saturday night's 21-18 after-the-siren win over Moana Pasifika.
The Force will assess him again before a final diagnosis is made.
But his expected absence will be offset by the likely return of Feleti Kaitu'u, who is in the final stages of his return from a minor hamstring injury.
"Folau took a shoulder to the head, which I think was a HIA, so that's why he didn't come back on," Force coach Simon Cron said.
"I believe it'd be 12 days (that he's ruled out). Nine times out of 10 (that's the case), but it hasn't been confirmed yet.
"We'll let that pan out and see what happens.
"But if he has problems or it's in the best interests of him for us to look after him, then obviously we've got Feleti in the background now, who's just built back (with running loads on Saturday)."
Force captain Michael Wells and lock Jeremy Williams are set to return from concussion for the start of the NZ tour, which will take in games against the Highlanders on Sunday, Blues and Hurricanes.
The Force are 2-1 after posting home wins over the Melbourne Rebels and Moana either side of an embarrassing 71-20 loss to the Reds.
Although the Force got the much-needed victory against Moana via an after-the-siren penalty from Bryce Hegarty, Cron wasn't happy with the performance.
"I think that we did a lot of things that we shouldn't have, and we could have applied a lot more pressure and built into that game a lot better," Cron said.
"I made it pretty clear to the backs that if we chip it again that I might make it onto the field and take them off myself, so I think the message was pretty clear."
And it seems the players weren't satisfied with their performance either.
"We talk a lot about being process versus outcome driven. So ignoring the score, process wise in terms of catch-pass, running lines, not offloading, not chipping the ball away - the players ranked themselves on-field quite low in that area," he said.
"It was under five out of 10.
"I would agree with that. The good news there is it gives us a lot of upside."
