The Sharks will enter Sunday evening's clash with Canberra in the midst of an injury crisis, with Rudolf one of five first-choice forwards sidelined.

Middle forwards Rudolf (ankle), Dale Finucane (eye socket), Braden Hamlin-Uele (knee) and Royce Hunt (calf) are all injured, while second-rower Briton Nikora remains suspended.

The absence of Rudolf is frustrating Fitzgibbon the most following last week's loss to the Tigers.

The Sharks prop was hurt when Bateman landed on the back of Rudolf's ankle after a tackle attempt, ruling him out for a month.

The NRL this week defended the lack of a charge, with head of football Graham Annesley saying Bateman's body weight had not come down directly on Rudolf.

It is not the first time the Sharks have been the victim of similar challenges.

Hunt missed five matches last year after being hurt in a Christian Welch hip-drop tackle that earned the Storm forward a one-match ban.

And fullback Will Kennedy missed six weeks in 2022 after an apparent hip drop from Souths prop Tevita Tatola that went uncharged.

Fitzgibbon was adamant no player deliberately commits a hip-drop tackle, but was frustrated his players continue to suffer ankle injuries.

"I'm confused about it, to be honest," Fitzgibbon said.

"I can understand the technical side of it, but we've got three players now with significant ankle injuries who have missed an extended period of time.

"And a grand total of one week's charge for those injuries.

"I don't know what the stipulations are. They give you some technical rule - but if you bust a player's ankle, surely it's got to be looked at.

"There's a clear difference between what the refs see, what the bunkers call and then what the match review committee do."

Canterbury appeared equally frustrated by the ruling on Good Friday, with South Sydney's Jack Wighton not penalised or subsequently charged for a potential hip drop on Jacob Preston.

The Sharks' forward shortage has prompted Fitzgibbon to move Siosifa Talakai from the centres to the second row against the Raiders, with Kayal Iro to debut in the backs.

Fitzgibbon said he would take a wait-and-see approach on whether the move would become permanent for Talakai, one of the biggest and most destructive centres in the game.

"Sifa has probably been our strongest player this year. But Sifa is also a strong back-rower. So it's a good debate," Fitzgibbon said.

"We've got Briton Nikora coming back the week after the bye (in round five) as well.

"We'll wait and see what plays out. We've got to get through this weekend before we get to anything."

Canberra have lost veteran forward Elliott Whitehead to a calf injury, meaning Corey Horsburgh will make his return to first grade after a suspension.

Australian Associated Press