Referees boss Tony Archer took the extraordinary step of releasing a statement after the match admitting Matt Cecchin was wrong in not sending Soliola off.
Soliola was placed on report and Slater left the field on a medicab with concussion.
A grade three charge for dangerous contact, the highest level available to the Match Review Committee, would have drawn 300 demerit points equivalent to a three-week suspension.
The lack of grading indicates the committee feel Soliola's hit is worthy of a longer ban.
In Soliola's defence, Slater was slipping as he made contact with his head and if he had stayed upright he could have been hit on the body.
It was out of character for Soliola, who has an outstanding reputation off the field and is one of the Raiders' most influential leaders.
But while the intention may not have been to hit Slater in the head, the shot was late and high.
If history is any guide, Soliola could face upwards of five weeks on the sidelines.
Of the 12 players referred straight to the NRL judiciary since 2002, five weeks was the lowest ban while Melbourne's Danny Williams has the record for the longest suspension with 18 weeks.
The most recent player to be sent directly to a hearing was Melbourne prop Jesse Bromwich who was cleared of biting in 2015.
In 2012, then-St George Illawarra forward Matt Prior was referred straight to the judiciary for knocking out North Queensland playmaker Johnathan Thurston with a late elbow and given a five-week ban.
- AAP
