Gavin Henson says he turned down an offer to stay with Toulon in order to resurrect his international career.
Toulon announced on Tuesday that the Wales centre had been released, based on financial constraints and his possible involvement at the World Cup.
Henson, 29, said he was not prepared to relinquish his chance of playing for Wales by agreeing to stay with Toulon.
"Playing for Wales and in particular featuring in a Rugby World Cup... is my number one priority," Henson said.
Henson joined the French club from Saracens in February in an attempt to relaunch his faltering career.
After a promising start where he scored a try on his debut, Henson's time in the south of France turned sour when he was suspended by the club for a week following allegations of off-field misbehaviour.
He was given a reprieve after an in-house investigation into the incident, and had harboured hopes of spending two more seasons at Toulon.
But Henson, who is set to play for Wales for the first time in over two years in June against the Barbarians, says those contract negotiations broke down when Toulon asked him to chose between the club and his country.
"I am disappointed that we weren't able to reach an agreement to enable me to play next season and beyond at Toulon, but for me the opportunity to try and prove myself for Wales is far too great to turn down," he said in a statement.
"It is true that we had discussions with Toulon and were offered an extended deal at the end of this season for me to remain a Toulon player.
"However during their meeting it became apparent that Toulon has an issue with me playing for Wales, basically giving me an ultimatum that I play only for Toulon, something I felt unable to commit to."
Toulon, who announced the signing of Willie Mason from Hull Kingston Rovers on Monday, will be without a host of front-line stars during the autumn when the World Cup is underway in New Zealand.
They include England's Jonny Wilkinson, Australia's Matt Giteau and Filipe Contepomi of Argentina.
Toulon team manager Tom Whitford said the club were not prepared to offer a contract to another player who could miss the first few months of next season.
Whitford told BBC Sport Wales: "The problem is we haven't qualified for Europe this season, which means that our budget is going to be restricted, which means then we're slightly limited in our salary budget - that's one reason.
"The second reason is we hope from his point of view he's going to be picked for the World Cup to play for Wales, which means we're going to lose a player for a three-four month period.
"So we'd rather not take that risk. Obviously there was an incident - and he wasn't the only one at fault, let's be honest about this - it wasn't just his fault.
"Having taken everything into account we've come to a decision whereby we're going to release Gavin and we're going to wish him very well in the future."
Henson's chances of making Wales' World Cup party improved when he was named in the squad to face the Barbarians at the Millennium Stadium on Saturday, 4 June.
Ironically, Henson could line up against Mason when Wales take on the Barbarians with the New Zealand-born player set to make his union bow in the match.
Toulon have also been linked with Melbourne Rebel Danny Cipriani, the out-of-favour England fly-half.
Henson's return following his ban by Toulon ended in a 27-3 defeat at Montpellier that killed off their French Top 14 play-off hopes.
The 2005 and 2008 Grand Slam-winner left the Ospreys in October for Saracens, where he returned to action after a controversial 20-month absence.
However, Henson's stint with the Aviva Premiership club lasted only four games and he arrived in the south of France with a calf injury.
That restricted the 2005 British and Irish Lions tourist to a limited role at Toulon, but he impressed in two-and-half-games before their season ended.