Kalyn Ponga could possibly have played his last NRL game this season with the Newcastle superstar in doubt for this weekend’s game against Cronulla.

The young gun is racing to be fit for the Knights’ round 24 clash at the Sharks on Sunday due to an ongoing ankle complaint.

“He’s in a (moon) boot at the moment,” Newcastle coach Nathan Brown told reporters on Thursday.

“We’ll give him every minute possible until Saturday but I’d be lying if I said he wasn’t doubtful.”

Ponga was moved from fullback to five-eighth last week due to the injury concern, with the 20-year-old setting up a first-half try in the Knights’ shock 20-12 win over Penrith.

Newcastle, sitting 11th and out of finals contention, are wary of allowing their young star to soldier on at less than full health.

“There’s going to come a stage sooner or later where he couldn’t keep going,” Brown said.

“I’m not sure what level of fitness he’s been at but he hasn’t been near 100 per cent.”

Brown said the nature of the injury means there is no guarantee Ponga will be available for either of the club’s final two matches.

“Some days you think it’s getting a bit better but (with) the load on it his problem’s getting a little worse,” he said.

“So whether he gets to the game this week or whether he gets to next week’s game is probably anyone’s guess at this stage.”