The St George Illawarra Dragons are 'confident' that Jaydn Su'A will avoid surgery, but have confirmed the second-rower will miss a number of weeks with a shoulder injury.

The club have also suggested Fijian winger Mikaele Ravalawa will be back for magic round at the latest.

Su'A, who missed Round 1, has played every game since for the Red V, but missed selection for next week's Anzac Day game against the Sydney Roosters.

It has now been revealed by the club's head physio Davis Theobald that he has a shoulder injury which will prevent him from taking the field, with the club confirming it was sustained at the back end of the game against the Raiders, and ultimately saw him leave the field after 74 minutes of action.

"Jaydn landed a bit awkwardly on his shoulder at the back-end of the Raiders game last Sunday," Theobald said.

"He subluxed the joint. It's essentially a small dislocation which comes back in itself.

"He is quite fortunate to not sustain a significant joint injury in the process. With some scans and specialist review in the last few days, we are pretty confident that he will avoid surgery and start some rehab today.

"We are looking at that three to four-week range. His stability is pretty good so it will just come down to his strength and function so we will just build that up and he'll be good to go."

Ravalawa last played in Round 6 against the Gold Coast Titans, missing the club's Round 7 clash with the Canberra Raiders, and not being named for Round 8 against the Sydney Roosters on Anzac Day. Tautau Moga has been used as his replacement in recent weeks.

"He has been back running for about a week now so we will continue to build that up and he should be on track for Round 10," Theobald told club media.

The Dragons will take on the Roosters in the traditional Anzac Day clash at 4pm (AEST).