Hull KR have been forced to de-register Australian halfback Michael Dobson to accommodate new signing Willie Mason on their overseas quota in time to play him against Crusaders on Sunday.

The 30-year-old former Australia Test forward, arguably the biggest overseas recruit in the history of Super League, is set to make his debut after flying into the country this week to take up a two-year contract with Rovers.

It was thought Mason had used his newly-acquired Tongan passport to enter the country and take advantage of a loophole in the Rugby Football League's overseas quota regulations through the Cotonou Agreement, a treaty agreed 10 years ago by the European Union and the Pacific nations.

However, it now appears the player used his New Zealand passport to enter the country and, therefore, must count on the club's five-strong overseas quota.

Dobson, who has been ruled out for up to two months with an ankle injury, has been taken off Rovers' register to make way for Mason, who will tomorrow be named in coach Justin Morgan's 19-man squad.

In a statement, Hull KR said: "At the present time, the club awaits final clearance on Willie's Tongan passport which is anticipated in the next few days.

"In the circumstances, Michael Dobson has been de-registered to free up a quota place.

"Once Willie's passport formalities are completed and Michael Dobson is again fit to be selected, he will be re-registered."

The RFL confirmed that Rovers met Thursday's deadline to register the player in time for him to play this weekend.

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