The Broncos have taken an early guilty plea for the grade-two dangerous tackle charge, resulting from Carrigan's high shot on Canberra forward Morgan Smithies in the 29-28 win over the Raiders in the qualifying final.
Carrigan, who was sin-binned, will miss Sunday-week's preliminary final at Suncorp Stadium against either Canterbury or Penrith but will be available for the grand final if the Broncos make it through.
It comes as another blow to the side after five-eighth Billy Walters suffered an ACL injury against Canberra.
Brisbane do have giant prop Xavier Willison available for the preliminary final after he was cleared to return from a broken forearm.
Broncos football boss Troy Thomson told AAP why the club decided a trip to the judiciary was not worth it.
"It's just the risk involved," Thomson said.
"We have reviewed the footage and got some advice from legal and other football contacts I have.
"Unfortunately there was shoulder contact with the head and we thought that being able to downgrade it to a grade one came with inherent risks, so we have taken the guilty plea.
"We are fortunate that we have a terrific squad and there is that next man up (mentality) to do the job.
"We have some troops coming back too with Willison being available. Brendan Piakura may be OK too. He is seeing a surgeon today so we will see how he goes."
Back-rower Piakura suffered a suspected facial fracture against the Raiders.
Captain Adam Reynolds, five-eighth Ezra Mam and outside back Selwyn Cobbo all trained strongly on Monday morning in another boost for the Broncos.
All three injured hamstrings in the round-23 loss to Melbourne.
Brisbane have also entered an early guilty plea for fullback Reece Walsh after his controversial headbutt on Hudson Young.
Walsh, who was sin-binned, also received a contrary conduct charge on top of the striking charge after he "flipped the bird" at the crowd as he left the field.
Several pundits have suggested Walsh's penalty for the headbutt should have been harsher but NRL CEO Andrew Abdo said he was comfortable with the punishment.
"This is something that's reviewed by the match review committee," Abdo said.
"They look at precedent and they look at the appropriateness of the conduct and on this particular occasion he was given a grade-one striking (charge), which is pretty consistent with what we saw through the season.
"Obviously we don't like to see instances of this off the ball but they made their ruling and we're very comfortable with it."
Walsh will pay $4800 in fines for both misdemeanours.
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