Sea Eagles prop Toafofoa Sipley could be facing a lengthy ban after he was referred directly to the NRL judiciary for a hip drop tackle.
He was sin-binned for the tackle on Dragons winger Mat Feagai in the 52nd minute.
He limped from the field and played no further part in St George Illawarra’s 20-18 win.
Feagai will go for scans on a possible serious leg injury that could sideline him long-term.
Sea Eagles captain Daly Cherry-Evans said post-match Sipley “might have been concussed and then lost his legs” while making the tackle.
“It looks pretty accidental from what I saw,” he said.
Manly had their misery compounded during the match with injuries to Nathan Brown (shoulder), Jake Trbojevic (concussion) and Tommy Talau (leg).
The trio are expected to miss the round-eight clash with Penrith.
Coach Anthony Seibold also confirmed the side would be without hooker Lachlan Croker for a month after knee surgery.
The Sea Eagles have now lost their last three matches to slide out of the top eight after being second in round four.
Seibold said star fullback Tom Trbojevic was on track to return against the Panthers at CommBank Stadium next Saturday night.
Meanwhile, Storm duo Tui Kamikamica and Ryan Papenhuyzen, Bulldogs forward Viliame Kikau and Souths prop Davvy Moale have been charged for offences on Good Friday but have escaped bans.
Kikau and Kamikamica were pinged $1800-$2500 for careless high tackles, Moale and Papenhuyzen have been fined $1000-$1500 for dangerous contact charges.
