Liam Williams will "definitely" be a Wales wildcard selection after he joins Saracens in 2017-18, says former Test centre Tom Shanklin.
Ex-Saracens and Cardiff Blues centre Shanklin believes another leading player could miss out under selection rules for players based outside Wales.
In November Rhys Priestland lost out to Taulupe Faletau, George North and Jamie Roberts over Wales' rules.
"Someone else will potentially lose out," said Shanklin.
Under Wales' selection rules, only three players based outside the country can be picked.
Williams, 25, will join the English and European champions from Scarlets on a three-year deal starting in 2017-18.
Shanklin, who won 2005 and 2008 Grand Slams with Wales, added: "Something will have to give.
"I suppose it's whether that law is abided by or not. He will definitely be one of [the wildcard picks].
"He has to be one of them, especially if Wales are in this transformation period where they're trying to play a different brand of rugby because he is key to that.
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"If he plays at 15, because I think he can make more of an impact on the game there, Wales can play differently.
"All of a sudden you open up an off-loading game, a more open, attacking threat and the Welsh team become more attack-focused."
Shanklin's former Wales captain Michael Owen - also an ex-Saracen - believes Williams will improve because of the move to the Premiership team, who are reigning European Champions.
"In many ways he will benefit from the move as a person and as a rugby player," Owen told BBC Radio Wales.
"Going back to the Wales squad, he would probably mature.
"He will probably become a better player from being exposed to different coaches and methods, so it will benefit Welsh rugby as well."
And Williams' former Scarlets team-mate Rhys Priestland says Saracens' new recruit will make them stronger.
"It's a fantastic move. He's certainly one of the best players in Europe," Priestland told BBC Radio Wales.
"I spoke to him about it and just gave him my opinion on the league.
"He's going to add a hell of a lot to their squad and he's going to make them an even stronger team."
The Welsh Rugby Union said it had made "the best offer" it could to ensure Williams stayed in Wales.