London - Rhys Webb's international future is in doubt after the Welsh Rugby Union confirmed on Thursday that he would be leaving the Ospreys to join a French club next season.
Webb has been Wales coach Warren Gatland's first-choice scrumhalf since 2014 and added to his 28 caps during the summer when he made two appearances as a replacement in the British and Irish Lions' drawn series with New Zealand.
Injuries have interrupted his Test career, presenting opportunities to rival Gareth Davies, but his energy and running threat mark him out as one of Europe's most dangerous half-backs.
Gatland is only permitted to select four players from clubs outside of Wales -- a number that will drop to two in 2019 -- so Webb's departure is a blow to the Kiwi coach.
Established internationals Taulupe Faletau, Luke Charteris, Rhys Priestland, Jamie Roberts, George North and Liam Williams are already playing in the English Premiership, while Dan Biggar joins Northampton in June.
"In line with our intention to keep our best players in Wales, every effort to retain the player has been made," said a statement jointly issued by the Welsh Rugby Union and Ospreys, who play in the Pro 14 league.
"While the news is disappointing there is an understanding that on occasion market forces will make this impractical."
Webb, who is reportedly set to join Toulon for the 2018/19 season, said: "It's a huge wrench to be leaving the Ospreys after spending all of my playing career with the team.
"I have made lifelong friends on and off the pitch and I cannot speak highly enough of the quality of the coaching team, players and all of the staff involved within the Ospreys organisation."