St George Illawarra fullback Josh Dugan may be sidelined for up to six weeks after suffering a knee injury in a horror night for the Dragons as they crashed to one of the heaviest defeats in Charity Shield history.

And Greg Inglis threw a scare into the South Sydney camp after being forced from the field with a jaw injury but it was nothing compared to the fright the monster Rabbitohs side delivered to their NRL rivals with their thrashing of the hapless Dragons.

''The boys went in pretty confident,'' said Rabbitohs prop Sam Burgess, who laid on a try with a cross-field kick. ''We have worked hard in the pre-season so it was good for a few things to come off.

''Our defensive effort in the first half was pleasing, we let a few points in the second half and gave the ball up a bit easy so we can work on that but there were some pleasing aspects in defence.

''There are things to look at, we were rusty in certain areas and, personally, I missed a few tackles but we will fix that up for round one.''

Fielding a new look side which featured their six off-season recruits, St George Illawarra were never in the match and appear certain to be without Dugan for the March 9 clash with Wests Tigers after he was assisted from the field midway through the second half.

The NSW Origin fullback was fitted with a brace before leaving WIN Stadium and will undergo scans on Monday but the initial diagnosis was that he had suffered a medial ligament strain and could be sidelined for up to six weeks.

''It is always disappointing when you see high profile footballers go down but that is the game we play and it's just the way it is,'' St George Illawarra coach Steve Price said.

The way Dugan injured his left knee summed up the night for the Dragons as giant Souths prop George Burgess fell on it as he barged over for the Rabbitohs seventh try in the 57th minute.

With the pain evident on his face, Dugan's knee had blood smeared on it as he was helped by two trainers along the sideline to the St George Illawarra dressing room.

Rabbitohs coach Michael Maguire said the decision to take Inglis from the field in the 44th minute was precautionary but medical staff checked his jaw on the sideline after a head clash with Dragons prop Dan Hunt.

Inglis later said he was OK and did not require X-rays.

Even without Inglis, it was like boys against men as the giant Souths line-up ran roughshod over a Dragons team whose performance would have left supporters in the 14,633 crowd at WIN Stadium fearing a long season ahead.

While it is obviously going to take time for new combinations to gel, St George Illawarra were easily outclassed by a Rabbitohs team missing halfback Adam Reynolds (knee) and first choice five-eighth Luke Keary (pectoral).

Dylan Walker also came off with an ankle injury but he is expected to partner Reynolds at the scrumbase in the opening premiership match against the Sydney Roosters.

Dragons five-eighth Gareth Widdop was the pick of their new buys, but Price will have to decide whether to partner him with Sam Williams or Michael Witt.