The NRL will block Jack de Belin being named in St George Illawarra's official 21-man squad if there isn't a decision from the Federal Court in his case against the governing body before Tuesday's team-list deadline.

The Herald understands the Dragons could be forced to apply for a special exemption to play de Belin in next Sunday's blockbuster against the Eels should the 28-year-old be successful in his bid to have his standing down under the NRL's new no-fault policy overturned.

Waiting game: Jack de Belin. Credit:AAP

Justice Melissa Perry is expected to hand down her judgment this week after the parties argued over the validity of the rule during a four-day hearing earlier this month.

St George Illawarra coach Paul McGregor has already indicated he would be willing to rush de Belin back into his 17 as soon as he is available, raising the prospect he could return for a mouth-watering game at Bankwest Stadium.