Scans on Monday confirmed Dugan suffered ligament damage in Saturday's crushing Charity Shield loss to South Sydney and the best case scenario is he'll be back for the Dragons' round five rematch with the Rabbitohs.
St George Illawarra coach Steve Price will start the year as arguably the NRL coach under the most pressure and early results could be crucial.
The Dragons attack lacked imagination in 2013 and the early signs in the Charity Shield indicated they may again struggle to score points.
Losing their most dynamic attacking weapon Dugan for at least four weeks will put even more pressure on new-look halves pairing Gareth Widdop and Sam Williams to get things right.
NSW State of Origin fullback Dugan will meet medical staff in the coming days to map out his rehabilitation schedule.
"Josh has had scans and a surgical review and has suffered a lateral ligament injury following a collision on Saturday," said Dragons High Performance Director Andrew Gray.
Elsewhere in injury news, Penrith have received some good news with Jamal Idris and Tim Grant both a chance to play in round one despite copping knocks in a trial match on Sunday.
Idris suffered a hamstring strain but the Panthers say he's touch and go to play Newcastle on March 8, and at worst should only miss the opening week.
Grant popped a rib, which went back in on the spot.
The NSW front rower has pulled up sore but officials don't expect him to miss any football.