The South Sydney Rabbitohs will be without star forward Keaon Koloamatangi for an extended period of time after he sustained an injury on Thursday night.

In what is a massive blow for the club, he sustained syndesmosis during a tackle against the Dolphins.

He has since been spotted wearing a moon boot on Sunday morning whilst inside the Rabbitohs Centre of Excellence in Maroubra.

According to The Daily Telegraph, Koloamatangi is expected to miss approximately six to eight matches but could be out for longer if he needs to undergo surgery.

The injury also means it will end his hopes of making his debut for the New South Wales Blues in State of Origin as he won't be recovered in time.

Blues coach Brad Fittler has previously stated that he has a strong respect for the forward and it was expected he could fulfil one of the four bench positions.

In the absence of the Tongan international, either Jai Arrow or Jed Cartwright are expected to fulfil the vacant back-row position. This means that Michael Chee Kam is the likeliest to come into the squad on the interchange bench.

The Rabbitohs will come up against the Penrith Panthers on Thursday night which is sure to be a blockbuster clash.