The injury also means Hopgood cannot come to Queensland's aid as coach Billy Slater attempts to pick up the pieces from the 38-18 thrashing the Maroons received in Origin II.
Queensland's bench forwards offered little at the MCG on Wednesday night and Hopgood would have been in the frame to make a second Origin appearance in the decider on July 17.
Instead, consultations with a specialist doctor on Thursday left Hopgood preparing for 12 weeks on the sidelines, with the regular season set to end in 11.
The only way Hopgood will play again this year is if the last-placed Parramatta manage to make finals, which would likely require the side to win nine of their last 10 games.
Hopgood is set to undergo a microdisectomy, a procedure usually undertaken to ease pressure on the spine caused by a herniated disc.
A big shot from NSW's Liam Martin inflamed the pre-existing back injury during the Origin series opener earlier this month and Hopgood has been struggling since.
The lock forward played restricted minutes in the loss to Canterbury five days after his Origin debut but pulled up sore before the Eels' most recent game against the Sydney Roosters.
Hopgood has completed light training with the Eels since that 28-18 loss but was not passed fit for selection in Saturday's clash against Newcastle.
He joins injured teammates Kelma Tuilagi, Bailey Simonsson and Ofahiki Ogden on the sidelines.
Hopgood's long-term absence is the latest in a string of blows for the Eels, who sit on the bottom of the ladder for the first time since 2018.
Injuries to star players Mitch Moses and Clint Gutherson have worked against Parramatta this season, with the club also in the headlines following poor results and the decision to fire long-term coach Brad Arthur.
Through two disappointing seasons for the team, Hopgood has been a shining light and one of the buys of the season in 2023.
He was the only Eels player selected for Origin in the series opener and is averaging more than 100 metres per game for the second season running.
Hampered by back issues early in his career, Eels five-eighth Dylan Brown said patience was the only way to approach an injury like Hopgood's.
"You never know what's going on (with back injuries), one week it can change, one week you can feel amazing, next week you can't move," he said earlier this week.
"It's just so long and they can't give you a time for it. They can't be like: Six weeks and your back's going to be sweet."
Brown said Hopgood had been positive despite the setback.
"He tries to get in as much (training) as he can, almost gets in trouble doing so. He's still in high spirits," he said.
10°C