Dragons forward Jack de Belin.

The NRL on Monday announced it has added the no-fault stand down policy to its rules, with Jack de Belin, Tyrone May and Dylan Walker informed they have been prevented from playing until court cases involving them are concluded.

On Thursday de Belin will resume a legal challenge to the implementation of the policy at the Federal Court in Sydney, just two days prior to the Dragons season opener against North Queensland in Townsville.

The new rule was added to the NRL Rules on Monday, giving effect to the February 28 policy announcement of the Australian Rugby League Commission.

The rule will see the automatic no-fault stand down of players charged with serious criminal offences and grant the NRL CEO discretion to stand down players charged with other criminal offences, particularly those involving women and children.

In a media release, NRL CEO Todd Greenberg said the new rule had been notified to all 16 clubs.

With de Belin now needing to be successful in court to be permitted to play, Dragons back-rower Tariq Sims said his brother Korbin looms as the long term replacement if de Belin is unsuccessful.

De Belin trained with the Dragons in Wollongong on Monday.

Australian Test forward Tyson Frizell moved from right second-rower to the middle in place of de Belin during the Charity Shield against South Sydney and is expected to play there on Saturday night as Korbin Sims is unavailable due to suspension.

The new rule was added to the NRL Rules on Monday, giving effect to the February 28 policy announcement of the Australian Rugby League Commission

However, the switching of Frizell created defensive issues on the right edge as Rabbitohs rookie Corey Allen scored a hat-trick of tries.

Sims believes the inclusion of Korbin after his two-match ban could be a long-term solution if de Belin is unable to play while he defends sexual assault charges.

"We get Korbin back after a few weeks ... he plays the exact same game," Sims said.

"He hits through the middle, he ball-plays really well, takes some smart options defensive-wise and he will be a really good player for us."

Besides Frizell, the other most likely option for the lock spot would be prop Blake Lawrie, who played 55 minutes of the 36-24 Charity Shield loss to Souths in Mudgee after a HIA sidelined Blues front-rower Paul Vaughan early in the game.

Dragons signing Korbin Sims.
Dragons signing Korbin Sims. ©Gregg Porteous/NRL Photos

Lawrie made nine Telstra Premiership appearances for the Dragons last season, including two finals matches, and is expected to become a more regular fixture in the top squad after the departure of Leeson Ah Mau to the Warriors.

"Jack is our starting lock, he played for NSW last year and has become a leader in our forward pack so if he is not there it is certainly a big loss," St George Illawarra captain Gareth Widdop said.

"We are not going to pick up a player like Jack but we just have to adapt to that. We have got no other option."

Sims said the St George Illawarra forwards were determined to leave their mark on opposition packs irrespective of who fills each role.

"We have got myself, Paul Vaughan, James Graham, Jeremy Latimore, Tyson Frizell – there are some pretty handy players who do bring a lot of spirt, and pride and passion, in their games,” Sims said. "If that means we all have to lift another 5 per cent then so be it".

While the immediate focus is on the make-up of the Dragons side to play the Cowboys, the players and club are concerned about de Belin's welfare.

"We need to make sure we are there for Jack. Obviously, his welfare is the most important thing but he seems to be OK," Widdop said.

"It’s there but it is not going to be a distraction, we can't let it be because we have got a job to do."

Dragons coach Paul McGregor is due to announced a 21-man squad at 4pm Tuesday for the trip to Townsville.