Flanker Jack Willis has signed a new three-year deal with Toulouse, potentially putting his England future in doubt.
He was allowed to play in the Six Nations because of "exceptional circumstances" surrounding Wasps.
Willis, 26, will be available for the World Cup this autumn, after which England's restriction on players based abroad is set to be reinstated.
The Rugby Football Union (RFU) and Premiership Rugby have a rule whereby players selected for England must compete in the Premiership.
A regular starter for Toulouse, Willis became England head coach Steve Borthwick's first-choice openside flanker in the Six Nations.
His contract with the French club was due to expire at the end of this season.
Willis spoke during the Six Nations of his hopes for a rule change, telling the BBC's Rugby Union Daily podcast: "At Wasps we were a victim of financial struggles.
"There's lots of clubs feeling that same pressure [and] that pressure needs to give in some shape or form.
"Some of those higher earners, maybe that is a solution to look to relieve that pressure, that they are earning their salaries abroad.
"There are lots of things to consider and it is not the most straightforward solution but I definitely think it is something that should be on the table in those discussions."
Other England players are also heading abroad for next season. David Ribbans will compete at Toulon, Joe Marchant is heading to Stade Francais, Sam Simmonds will play for Montpellier with Jack Nowell also set to sign for the French club.
Luke Cowan-Dickie is expected to move to Montpellier but is currently injured.