The decision came after a 90-minute hearing by the NRL judiciary on Tuesday night.
It means the Broncos will be without Carrigan until the last week of the regular competition. But it means Carrigan will be free to play assuming the Broncos make the finals.
Brisbane is currently fifth on the NRL ladder.
Carrigan had pleaded guilty to a dangerous contact charge for an incident in the 73rd minute of Brisbane's shock 32-18 loss to the Tigers last Saturday night. Hastings was bent back over Carrigan, with his ankle twisting underneath.
