Kalyn Ponga will be racing the clock to be fit for Week 1 of the NRL finals series, with the Newcastle Knights confirming he has suffered a "high grade" AC joint injury.

Ponga was hit in a tackle during the final minutes of Sunday's big win - the eighth straight for the Knights - against the Cronulla Sharks.

While he originally attempted to stay on the field in clear discomfort, he was eventually taken to the dressing rooms for assessment.

The club confirmed to Fox Sports towards the end of the game that Ponga would need to go for scans, but they were hopeful the injury wasn't serious.

The club however have now confirmed a high grade AC joint injury which will rule Ponga out of Round 27, although they are hopeful that he may be available for the first week of action in the finals.

"Scans today have confirmed nib Newcastle Knights Captain Kalyn Ponga has a high-grade AC shoulder injury," the Knights wrote in a statement.

"Ponga will not be considered for selection for Round 27, medical and performance staff have commenced treatment with a view to returning for week one of the finals series."

AC joint injuries of a higher grade usually require more than a single week out of action, meaning Ponga will be at best racing the clock to feature in what will be a home elimination final.

RELATED: How every Round 27 game impacts the final ladder

The Knights' win over the Sharks on Sunday means they can't fall lower than sixth on the table, and will host either the seventh or eighth-placed team in the opening week of the finals series.

McDonald Jones
   Crowd: 29,423

Before that though, the Knights will take on the St George Illawarra Dragons in the final game of their regular season, with coach Adam O'Brien promising during his post-game press conference on Sunday that he would rest any players who have a bump or niggle.