Ben Trbojevic has labelled criticism of his brother Tom's form as unfair, with Manly players adamant the fullback can again reach the heights of his record-breaking 2021 season.

The Manly star remains the centre of focus at the Sea Eagles for the past month after battling a groin injury and having his NSW spot called into question.

There have been external claims Trbojevic is playing within himself, only breaking into full flight on a limited number of occasions this season.

After a shoulder injury cut short his 2022 season, Trbojevic suffered a fifth hamstring injury in five years over the summer before a stint of reconditioning in the USA.

The 26-year-old has scored five tries in eight games this year, while also setting up another five and busting three tackles per game.

Manly are still a more threatening team with Trbojevic on the field, but the numbers are well down than on his 2021 run to the Dally M Medal.

"I feel like he is getting a bit of unfair criticism," Ben told AAP.

"You look at every game he has played this year he has gone pretty well. He may have had one off game.

"You look at the stats in every game he plays, if it was any other fullback not named Tom Trbojevic you would say he has played a pretty good game.

"2021 was crazy, but this year, he is still playing good footy."

Ben predicted the criticism would spur Trbojevic to prove a point against Cronulla on Sunday.

"I think it will," he said.

"Hopefully this week he gets out there and smashes it. That will be good.

"He's a very focused, professional athlete. He is keen to get out there and play his best footy and get a bit of confidence about himself."

The comments are not the first time Manly have urged critics this season to not compare Trbojevic to his 2021 season.

That season remains in the conversation for the greatest individual year of all-time, after Trbojevic scored 28 tries and set up 31 in his 18 games.

But Manly winger Reuben Garrick remains adamant the fullback can return to that level.

"I think he knows he can, and we all know he can," Garrick said.

"He's a tremendous athlete. He's not too far off, and in his mind he definitely knows that he can.

"Any other person probably couldn't do it but for him, it's not untouchable."

Manly prop Aaron Woods also backed Trbojevic to regain that form, but said teammates had to help.

"We as a group need to play better footy to create some more opportunities for him," Woods said.

"A lot of the time it looks like we're just going out the back and hoping that Tom can create something.

"But if we can get some better play-the-balls in the middle and our edges run some better lines to hold up defenders, that will bring back that form."