Ponga was sin-binned late in Friday night's loss after a collision with Wests Tigers second-rower Michael Chee Kam that has left him in hospital as a precaution.

Chee Kam, Ponga and Knights winger Hymel Hunt were in pursuit of a 78th-minute Benji Marshall grubber when the three players collided.

Replays later showed Chee Kam was nudged from behind by Hunt, propelling his head into the tucked left shoulder of Ponga.

The game was stopped for at least five minutes before Chee Kam was taken from the field in a medicab before being taken to John Hunter hospital.

Ponga was subsequently marched following a review into the incident but later defended his role in the collision.

"I was a bit surprised. I don't know what the refs wanted me to do there, maybe let them score, I'm not too sure," Ponga told AAP.

"Obviously he was heading for the ball. I dived with the intention to bat it at first and then obviously saw that he was right there and braced for impact.

"I did hit his head which I'm obviously concerned about.

"But at the end of the day, I gotta shield myself as well. Straight after he looked in all sorts. It was pretty bad. I hope he's alright now."

Knights coach Nathan Brown thought it was a stiff decision at a time when his team were trailing by two with two minutes to remaining in the contest.

"It's not what cost us the game but I think Kalyn's playing fullback and he's making a play. He's got to make a play. He can't just stand there," Brown said.

"He's a bit unfortunate. I don't think there's a cleaner player playing the game."

The incident comes less than a week after criticism of Penrith star Viliame Kikau being handed a two-game ban for a grade-one shoulder charge.

He was originally sin-binned for a late shot.

A grade-one shoulder charge attracts a 200-point penalty, which would mean Ponga would have to plead his case at the judiciary to avoid suspension.

Even a one-game absence would be a serious blow for the Knights, who could drop out of the top eight by the end of the weekend.

"I don't think he tried to make a shoulder charge," Brown said.

"I'm pretty confident he was trying to make a play for the ball. I don't think he was trying to shoulder charge anyone."

Tigers coach Michael Maguire described the contact as accidental.

"I think it was more accidental than anything. Obviously they were competing for the ball. I'd have to see it again in close vision," he said.

"I could only have the wide vision on that one. I'll wait and see how it pans out."

Australian Associated Press