Hopgood was injured in the first half of the Eels' 30-20 win after Dragons forward Ryan Couchman fell on the back of his legs.
The 26-year-old limped from the ground and Couchman was sin-binned, but Eels medical staff have already determined that the former Queensland State of Origin forward's season is over in March.
"It's really disappointing," Eels coach Jason Ryles said.
"Those tackles, 99.99999 per cent of the time the boys don't mean it. It's not intentional.
"But unfortunately you keep throwing fatigue into the game and you keep making them even more tired, they happen."
In a further blow for Parramatta, centre Jordan Samrani is also set for scans on his knee after limping off in the first half.
He is not believed to have suffered ACL damage.
It came as Tallyn Da Silva produced his finest day in Parramatta colours, scoring two tries and playing a role in another to help Parramatta come from 14-4 down to coast home.
While Parramatta are 2-1, the Dragons are winless after three games for the first time since 2020 despite being in each of the contests until late.
Ultimately, the difference at CommBank Stadium was what both teams were able to do when their opposition was down to 12 men.
With Parramatta trailing by 10 late in the first half, Mitch Moses and Da Silva proved vital while Couchman was in the sin bin.
Moses first made his impact when he ran the ball on the last tackle, catching the Dragons on the back foot and giving Jonah Pezet the space to send Da Silva in to score.
Moments later, Da Silva went to dummy-half for a quick Matt Doorey play-the-ball and sent second-rower Kitione Kautoga over to make it 18-14.
The Eels hooker then scored a try of his own after the break when he feigned to the right and darted over from close range at dummy-half.
After arriving as a high-profile mid-season signing from Wests Tigers last year Da Silva has spent most of his time coming off the bench, but this was his best outing so far.
In comparison, the Dragons couldn't nail the key moments when Parramatta's Charlie Guymer was sin-binned for a professional foul in the second half.
They scored once through a Moses Suli grubber for Kyle Flanagan, but otherwise failed to make the most of space to the left on multiple attacking raids.
The Red V's fate was sealed with Guymer back on the field, when Valentine Holmes spilled a pass and Josh Addo-Carr went 70 metres to score.
Earlier, drama surrounded the Eels' first points when Jonah Pezet was awarded a penalty try after being taken out by Clint Gutherson in support play.
Dragons coach Shane Flanagan confirmed afterwards he had no issue with the call.
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