London - Liam Williams has been told his prospects of playing for Wales next season could depend on a wildcard selection if he joins English Premiership champions Saracens.
There have been reports in the Welsh press that the 37 times-capped fullback or wing has agreed a two-year deal with Saracens, although the London club have not made any comment.
Now there is speculation that the 25-year-old Williams could move to Saracens in January.
Wales want the majority of their internationals to play their club rugby for one of the country's professional regional sides.
But the Welsh Rugby Union do have four wildcard places available to players featuring in club rugby outside of Wales in the 2017/18 season.
"We've said we want to keep our best players in Wales, and Liam is certainly one of those," said Wales assistant coach Neil Jenkins on Tuesday. "We would love to keep him in Wales.
"I am sure we will fight in every way possible to keep our best players, and Liam is one of them," the former Wales international added.
Wales fullback Leigh Halfpenny could also find himself on a list of so-called 'captured players' next year if he signs a new contract to stay in France with current club Toulon, rather than return to Wales.
"We have said from day one that we want our best players playing in Wales," said Halfpenny. "Leigh comes into that category, and so does Liam.
"We would love Leigh back, and we would love to keep Liam, there is no doubting that.
"If Leigh stays (in Toulon), if Liam goes, it does become an issue, obviously, but at some point in time it is an opportunity for other players as well."