The Dragons have suffered two major blows from Sunday's loss to Cronulla, with James Graham to miss two months with a broken leg and Tim Lafai out with an ankle injury.
Star prop Graham has been ruled out for eight weeks after scans revealed he'd suffered a fibula fracture.
Meanwhile centre Lafai suffered a syndesmosis injury and will meet with specialists to determine his time on the sidelines.
Sunday's loss was St George Illawarra's seventh of the season after 11 rounds and dropped them to 13th place on the ladder.
The Dragons have a bye this week, with their next match against the Bulldogs at ANZ Stadium on Monday, June 10.