Parramatta's Haze Dunster suffered a potentially serious knee injury in Sunday's 26-22 NRL trial loss to St George Illawarra after a hip-drop tackle that has Tyrell Fuimaono facing suspension.
Dragons centre Max Feagai was also forced off with an ankle injury in the second half while teammate Tautau Moga and Eels forward Ryan Matterson were sin-binned for high tackles at CommBank Stadium.
St George Illawarra fought back from 16-0 to be level at half-time as English prop George Burgess got through his first match since late 2020 following radical hip-resurfacing surgery.
The former South Sydney bookend, who left the NRL after the 2019 season to join Super League club Wigan, finished with seven runs, 55 metres and five tackles in a solid stint off the bench.
Parramatta confirmed winger Dunster sustained "ligament damage" and will undergo scans after the winger was awkwardly caught underneath Fuimaono in the 13th minute.
"I think he'd be out for a little while," Eels coach Brad Arthur said.
Fuimaono was sin-binned and placed on report for the incident.
Due to his rap sheet, including a hip-drop offence in 2020, another last season as well as a reckless high tackle, the second-rower would have loading and carryover points applied to a potential charge.
Just two minutes after the Indigenous All Star was given his marching orders, Moga, in his first appearance in the Red V, was sin-binned for clocking new Eels winger Bailey Simonsson high.
Matterson, a late addition to Parramatta's squad, copped the same fate after a high tackle.
After starting on the wing, Tyrell Sloan traded places with Cody Ramsey at fullback during the first half in a strong 80-minute audition for the No.1 jersey.
Sloan threw a beautiful a cut-out pass to set up Jonathan Reuben's 63rd minute match-winner.
"(Sloan) was good, he got a little bit more confident as the game went along," Dragons coach Anthony Griffin said.
"He had some nice touches. He's got a lot of class. He did a good job for us."
Parramatta hooker Reed Mahoney returned from the shoulder injury that curtailed his 2021 campaign and his team were right on top while he directed play around the ruck.
Griffin said he was disappointed in his senior players as the Eels skipped to an early lead with tries to Hayze Perham, prop Oregon Kaufusi and winger Sean Russell.
Feagai, Connor Muhleisen and Moga - courtesy of a neat offload from centre recruit Moses Suli - returned serve before the break for St George Illawarra.
Solomone Naiduki put the Eels back in front in the 44th minute before Josh McGuire executed a run-around play to create space for Dragons winger Bailey Antrobus to touch down.
