Manly's Jamil Hopoate has had his potential NRL debut blocked by the game's integrity unit after it was deemed the troubled youngster still required further rehabilitation.
Hopoate, the son of former Manly bad boy John, served nine months in Long Bay jail after pleading guilty to two counts of of assault occasioning actual bodily harm in company, in December 2014.
The Sea Eagles wrote to the NRL this week in an attempt to have the 21-year-old debut against Penrith on Sunday night, but the move has been blocked by the NRL.
"The NRL has required Jamil undertake a range of rehabilitation work before it will consider registering his contract," an NRL spokesman told AAP on Thursday.
"That rehabilitation has not yet been undertaken."
Hopoate's contract was torn up by the Sea Eagles at the time of his sentencing over the February 2014 incident, having previously been shown the door by Parramatta in 2012 after misbehaving at an NRL rookies camp.
He was released from jail last October and returned to rugby league with Manly A-Grade club Narraweena in May, and was called up to the Sea Eagles two months later.
He has since played lock for Manly at NSW Cup level.
It's possible he could have been used in the Manly backline to replace the injured Dylan Walker in first grade.
Walker has been named at centre for the match, however the club's website says he is out for the season with a shoulder injury and was reportedly spotted in a sling last week, despite also being named.
Manly coach Trent Barrett suggested on Friday the club may be forced to bring some under-20 players into this weekend's team, but said he accepted the NRL decision regarding Hopoate.
"Jamil; he's eligible for NSW Cup but not eligible to play NRL," Barrett said.
"I'm not too sure of the details around that. Rules are rules and we'll abide by them.
"When our players are all okay to play, we'll play them."
It's the second time the NRL have blocked a Hopoate from rugby league involvement at Manly this year, after they also stopped John from coaching the club's SG Ball team.
Manly are also yet to have the contract of former Sydney Roosters youngster Willis Meehan registered with the NRL, after they signed him mid-season following his assault of a taxi driver last July.
"Similarly Willis will have to show he is fit and proper before he can return to the NRL," the NRL spokesman said.