Hull KR have de-registered prop Willie Mason following a protracted delay in the player obtaining a Tongan passport.
The Australian international would gain exemption from the club's overseas quota with the document.
Fellow Australian scrum-half Michael Dobson - de-registered with the Rugby Football League in March after an ankle injury - has duly been re-registered.
Re-registering Mason, subject to him obtaining a Tongan passport, would now require the RFL Board's full support.
Just a day before his de-registration - which was announced on Thursday - Rovers had insisted the 31-year-old remained part of their plans despite his continuing inability to play without taking up an import berth.
Along with insisting that they were making progress in pursuit of the passport, the club also quelled growing rumours of an impending move to French rugby union side Toulon.
Mason was even named in Rovers' initial 19-man squad for Friday's Hull derby at the KC Stadium but Dobson - who was de-registered on 10 March after undergoing ankle surgery in order to make room on the overseas quota for Mason - has now taken his place.
The club have yet to make any comment on the latest turn of events but the RFL says it has approved the change of registration.
A statement read: "The RFL can confirm that Hull Kingston Rovers have re-register ed Australian scrum-half Michael Dobson and that the player is eligible for selection for the Engage Super League Round 11 fixture at Hull FC on Friday, 22 April.
"Hull Kingston Rovers have also de-registered prop Willie Mason following a protracted delay in the player obtaining a Tongan passport.
"Any application to re-register Willie Mason, subject to the player obtaining a Tongan passport, would require the full support of the RFL board of directors."
Mason was last week spotted having talks with Toulon's wealthy president Mourad Boudjellal.
It is thought they want Mason to follow in the footsteps of his former Canterbury Bulldogs team-mate Sonny Bill Williams and play inside centre, having transformed the New Zealander from a rugby league forward to a powerful union three-quarter.
Mason, who signed a two-year contract with an option for a third season at Craven Park, made an impressive Super League debut against Crusaders six weeks ago - but has made little overall impact despite scoring his first try for Rovers against Wigan last Friday.