Inside the Roosters' celebrations for Jennings' 300th

Michael Jennings' "past conduct" meant he was not celebrated by the NRL ahead of his 300th game - but the Sydney Roosters held tributes of their own.

Premiership heroes from 2013 had a starring role as the Sydney Roosters delivered on their promise to celebrate Michael Jennings' 300-game milestone behind closed doors.

Ahead of Thursday night's clash against Newcastle, the NRL announced it would not mark Jennings' milestone with traditional festivities due to the centre's "past conduct".

Jennings tested positive to performance-enhancing drugs in 2020, serving a three-year ban. He was also found, following a civil case in the NSW District Court in 2021, to have sexually assaulted his wife four times during their marriage.

Jennings has yet to pay Kirra Wilden the almost $500,000 in damages ordered as part of the case she brought against him. He has not been subject to criminal trial and has denied Wilden's allegations.

As Jennings' return to the league divided fans, the NRL made clear that it would not stand in the Tricolours' way if they chose to celebrate the 35-year-old themselves.

Jennings led the Roosters out at McDonald Jones Stadium on Thursday night with his two children in tow, stopping for photographs to mark the moment.

After the Roosters' 22-20 win, Jennings' teammates immediately mobbed him in celebration.

"Just the way we've seen him come back, fight really hard for a place in the squad, he's been such a good influence on the squad," said five-eighth Luke Keary.

A group of Jennings' friends and family travelled to Newcastle for the game, including brothers George and Robert, who have had NRL careers of their own.

Jennings' 2013 premiership teammate Frank-Paul Nu'uausala was also in attendance, with family and friends gathering in the sheds post-game to share in the victory over drinks.

The entire party wore custom-made Jennings shirts, which featured photos of the centre in the jerseys of the three clubs he represented: Penrith, Parramatta and the Roosters.

Earlier in the week, the Roosters extended an invite to their 2013 premiership team to visit the club's headquarters and pay tribute to Jennings, who played at centre in that win over Manly.

Premiership captain Anthony Minichiello was among the visitors.

Such was the extent of the tributes, Daniel Tupou, one of only two other Roosters from that 2013 team still at the club, did not have the chance to make a speech.

"It was sort of a reunion of the 2013 team," Tupou told AAP.

"It was pretty emotional."

Tupou had the chance to commemorate Jennings' career on game day.

"It felt like we were running it back from 2013, 2014, and all those memories we created," Tupou said of the ensuing win.

"It's just a full-circle moment."

Roosters coach Trent Robinson doubled down on his support for Jennings post-match after receiving criticism from some quarters during the week.

"I'm really proud that he could lead his kids out there. He's the first Tongan to play 300 games," he said.

Robinson has already flagged that the State of Origin period could present more opportunities for Jennings to play at NRL level, with the back-line set to be reshuffled to compensate for Tedesco's likely absence.

"It's all in Robbo's hands," Tupou said.

"I'm confident he will get another few more games under his belt this year."