In addition, the Warriors expect to receive a proportion of the £700,000 ($1.4 million) they paid to Wigan to release Tomkins after the 2013 World Cup.

Whether that money is paid by whatever club signs Tomkins or the player himself is unclear but it may be the reason he has not committed to a return to Wigan next season, as had been expected.

"That's where my brother [Joel] is playing and that's where I'm from, but I'm open to other places," Tomkins said after the announcement. "I'm just trying to work out what will be the best option for me. Wigan would be nice but I know it's not the only team I can go to."

In announcing his departure 18 months ago, Wigan said they could re-sign Tomkins on a "defined salary" if he returned to the Super League but the club's chairman Ian Lenagan has confirmed they merely have first option on the services of the 26-year-old.

The increasing trend of clubs paying transfer fees to secure players under contract elsewhere has led to the NRL including such payments under the salary cap but, because the Warriors deal with Wigan preceded the new rule, any money they receive back will not have an impact on their cap.