The Dragons forward was seen on a stretcher and wearing a neck brace, being assisted by paramedics from the training ground at Wollongong's WIN Stadium.
A club statement confirmed Pasifiki Tonga had avoided major injury after undergoing precautionary scans.
"The Dragons can confirm that following scans, Loko Pasifiki Tonga has been cleared of any major neck injury concerns and returned to the Dragons training facility this afternoon," the statement read.
"He will be monitored by our medical staff over the coming days before a determination is made on his availability to play this weekend."
Rated one of the club's best up-and-coming forwards, Pasifiki Tonga had been listed to play in Sunday's NSW Cup clash against Parramatta.
While the club is yet to make a call, the Auckland-born 20-year-old appears unlikely to line up in that fixture, which will be played at CommBank Stadium prior to the teams' NRL clash.
Pasifiki Tonga made his NRL debut in round 10 last season and has played all 10 of his first-grade appearances to date from the bench.
He has not played in either of the 14th-placed Dragons' first two games this season but is contracted until the end of next season.
