The Parramatta Eels will be without youngster Richard Penisini for the entirety of the 2024 NRL season after he suffered an ACL injury.

The injury, which occurred during pre-season training, will see Penisini - who is the younger brother of star centre Will - out for a period of between nine to twelve months.

In the best case scenario, he would be fit to return to the start of pre-season training for the 2025 season.

It's unclear exactly when the injury occurred, with the club confirming the youngster has already undergong surgery and commenced his rehabilitation program from the injury.

Rated as one of the best youngsters in Parramatta's junior system, Penisini made his NSW Cup debut at the back-end of the 2023 season against the Sydney Roosters, and likely would have worked his way into being a mainstay in that set up during 2024 as he pushed for a first-grade debut.

Given Parramatta's lack of depth at centre and in the backline more broadly, as well as some of the struggles Brad Arthur's side faced in the position throughout the 2023 campaign, there were even some speculating that the youngster could well have been in line for an NRL debut during the second half of this year's campaign.

That will now not be the case, with Richard needing to instead rehabilitate his knee.

He has been regarded already as one of the key reasons brother Will - who is cemented in the first-grade side - re-signed with the club on a long-term deal despite interest from rugby union.

โ€œYeah, 100 per cent. It's a dream for him to be able to debut for the club and a dream for us as brothers to be able to play together for the Eels,โ€ Will had told News Corp in mid-2023

โ€œIt'll be a huge moment for my family if it does happen. I know he's got a long way to go but I think getting an NRL pre-season under his belt going into next year will help get him close to that dream.โ€

The younger Penisini's news has been offset at the Eels by the confirmation from the club that Ryan Matterson is back to full training, and that fellow forward Wiremu Greig should be back on the training track in the coming weeks.