It was something of a surprise when Saifiti was left out of the Knights side yesterday.
Coach Adam O'Brien had previously said Saifiti would be good to go for Round 1, having been left out of the Knights' second trial against the Storm a week later.
At the time, O'Brien commented that it was just soreness which had kept him out of the match.
"Yeah, look, they'll be fine for Round 1," O'Brien told Fox League ahead of the match.
"Daniel has a sore foot and Jacob jarred up his back at training.
"With the flight down, they weren't worth the risk. They'll do some training in Newcastle and be right for Round 1."
It has since been revealed that Saifiti suffered a leg break from the tackle, and it has left the Knights seeing red.
Thompson escaped the incident with only a fine, which has left the Canterbury enforcer free to play this weekend when the Bulldogs open their season against the North Queensland Cowboys on Sunday night.
The Knights, meanwhile, will take on the Roosters without their Origin enforcer. The Daily Telegraph are reporting Saifiti could miss up to four weeks, which could also see him miss important clashes against the Wests Tigers, Penrith Panthers and Cronulla Sharks.
The publication report the Knights can't understand why the incident wasn't pulled up at the time, with the tackle looking as ugly as the one from St George Illawarra Dragons enforcer Tyrell Fuimaono which ended Parramatta Eels' winger Haze Dunster's season just 24 hours earlier.
Fuimaono copped five weeks for his tackle.
Judiciary changes are reportedly on the way - and could be announced as soon as Wednesday - but it hasn't come soon enough for the Knights, who will now rely on Daniel's brother Jacob to start alongside David Klemmer, while youngster Leo Thompson has been handed a debut off the bench.