At a meeting this week, NRL CEOs talked about inserting a clause into every player contract, prohibiting them from trying out with NFL franchises.
The initiative comes after the high-profile trip Jason Taumalolo and Valentine Holmes took to trial in front of NFL scouts last month.
Similar restrictions already apply to AFL and union.
“The clubs have made it clear that they don’t want their players going to another code, including NFL, and risking serious injury,” NRL CEO Todd Greenberg told News Corp.