Warren Gatland says Taulupe Faletau's Wales career will be "protected" should he leave Dragons for Bath.
Under the so-called 'Gatland's Law' selection policy, Wales-based players are likely to be favoured for Test selection over those who choose to play elsewhere.
But the Wales coach said that as Bath have come in for Faletau, his international career could continue.
"It's not his decision if someone comes looking for him," he said.
He added that the Rugby Services Agreement between the Welsh Rugby Union and Pro Rugby Wales ensures players in Faletau's position would not be excluded from Test selection.
Gatland said the English club have offered a significant transfer fee to buy Faletau out of the remaining year on his deal and added: "He's still in contract and they've offered a significant transfer fee... that is a business decision [for Dragons] to potentially sell that player on because they are struggling financially.
"And so that [proviso] wasn't argued by us. That was argued by the regions... that's why if Toby does go he is protected [in terms of Wales selection]."
Faletau, he said, is happy at Dragons but the region are "struggling financially".
"The person who's got the biggest choice to make about this is Toby. Obviously our preference is for players to play in Wales and we want that to happen.
"I don't think he's that keen on going to any other regions.
"He'd [Faletau] see an opportunity perhaps to go across the water and that would pacify a few people in terms of the tribalism that is in Wales.
"Maybe it's a good challenge for him. He's given some excellent service to the Dragons."
Cardiff Blues have also made a bid to sign Faletau and are awaiting a reply from the player's agent.
In May Wales withdrew a national dual contract offer to the Tongan-born British and Irish Lion.
That would have kept Faletau at Dragons beyond the end of the 2015-16 season.
Gatland says talks between Wales, Bath, the Dragons and their fellow Welsh regions are continuing.
"That's ongoing and hopefully they can sort it out in the next week," Gatland said.
Gatland also says the deal Bath have offered to Faletau means like Harlequins-bound Jamie Roberts and Northampton's George North, he will be free for all Wales training and playing commitments.