The NRL plans to investigate comments directed at match officials by Sydney Roosters coach Trent Robinson.

The Roosters kept pace with the reigning premiers on Friday night but couldn't close the game out after earning only 28 per cent of the territory and finding themselves on the wrong end of an 8-3 penalty count.

After the 26-18 loss at BlueBet Stadium, Robinson lamented a series of "big decisions" from referee Gerard Sutton that he believed cost his side.

Robinson questioned Sutton's decision to sin bin Angus Crichton after the play had moved past his professional foul and was also critical of a dangerous tackle penalty blown against Sam Verrills that put Penrith in position to score.

"(The penalty against Verrills) was just a horrible decision," Robinson said.

"We shouldn't have let a try in on the end of it but there were so many poor decisions tonight.

"The sin-binning ... we're not playing rugby union. You either stop the game and send him to the bin or you don't.

"They're big decisions that you can't get wrong."

Robinson appeared to suggest Sutton chose not to award penalties to the Roosters that he would have paid the Panthers.

"It wasn't a good enough performance from him," he said.

"It wasn't going to happen in Roosters' colours. That's not bias, that's a fact, that you're not going to get those opportunities.

"Obviously there were issues there with our team and not the other team."

In August last year, the NRL fined Robinson $20,000 for comments made about the officiating of the Roosters' loss to South Sydney.

On that occasion, Robinson labelled the match officials' performance "laughable", triggering a $10,000 suspended fine imposed earlier in the year for another post-match critique.

The NRL told AAP on Saturday that Robinson's most recent comments would be reviewed next week, but there was no time frame on finalising its investigation.

Captain James Tedesco consulted with Sutton throughout the loss but said there "wasn't much explanation" for the skewed penalty count.

"It was frustrating. It felt like we were defending our line so well and then we would just get a penalty against us," he said.

Panthers coach Ivan Cleary was brief when asked whether he agreed with Robinson's assessment of the refereeing.

"I didn't see it like that," he said.

Victor Radley left the field for a head injury assessment late in his first game back from an ankle injury but Robinson said his lock forward would not face more time on the sidelines.

"He didn't even know why (he was taken off)," Robinson said.

"He's fine."

The Roosters have the bye in round 17 but Robinson said playmaker Luke Keary would make his return from a head knock the following week.

"That's the plan, that's what he's working towards," Robinson said.

"He's back on some of his progressions to get towards that."

Keary suffered five concussions between 2018 and 2019 so the Roosters are managing his return with extra care.