Wales coach Warren Gatland says Dan Biggar will need to make a strong start at new club Northampton to keep his international place next season.
Biggar has left the Ospreys to join the English club but is still be eligible to play for Wales.
Cardiff Blues' Gareth Anscombe and Scarlets fly-half Rhys Patchell are rivalling Biggar for the Wales 10 jersey.
"He needs to be playing well for Northampton next year," said Gatland.
The Welsh Rugby Union want their top players staying in regional rugby and brought in a new rule brought in meaning anybody taking up a new contract with a team outside Wales must have won 60 caps to be able to play for their country.
Biggar has won 62 Wales caps but will not have the same preparation time as his main number 10 rivals because he is now playing in England.
The British and Irish Lions 2017 tourist has been rested for this summer's Wales trip with Patchell and Anscombe the two fly-halves in the party.
Anscombe started against South Africa while Patchell has been given the opportunity against Argentina.
"If you don't have the same preparation time and you're not released as frequently as the Welsh-based players, you're putting your selection in some jeopardy," said Gatland.
"The players understand that, they're not happy about it, but they're the ones who have made the decision to leave and play outside Wales.
"The latest one is Dan Biggar. He needs to be playing well for Northampton, the team needs to be playing well, because you want a fly-half coming from a team with confidence.
"He's aware of that. The ideal situation is to have players playing in Wales, but also them playing too, so there's a balance to be had.
"The conversation I have with players and staff - it's the same for both - is they have to make the decision that's best for them and their families.
"They take the risk by not playing in Wales and we've had a few players that have left."
Second chance for Adams
Worcester wing Josh Adams, along with Exeter prop Tomas Francis and Bath lock Luke Charteris, found themselves released from the Wales touring squad to play South Africa.
This happened after Premiership Rugby, the organisation that represents the English clubs, refused the trio's release for the South Africa match because the game in Washington DC was outside the international window.
Following Wales' 22-20 win in North America, Adams and Francis have been called up to the squad for the Argentina leg of the tour.
The 23-year-old starts on the wing in the first Test against the Pumas after replacing the injured Steff Evans, while Francis is named on the replacements bench.
Adams won two caps in the 2018 Six Nations against Scotland and England and finished the Aviva Premiership as the league's joint top try scorer.
Gatland has backed him to impress after his initial disappointment.
"Josh took it on the chin," said Gatland.
"I've made my feelings and disappointment quite clear on that subject.
"I know he was disappointed to be left out and he now gets a chance to show what he's capable of doing with a few players not here.
"He comes in with a lot of confidence. The fact he's had a good season and scored those tries will stand him in good stead."