WP Rugby is unhappy that Duane Vermeulen flew to France during the week of the Stormers' play-off qualifier.
The Stormers captain was officially unveiled as a Toulon player on Thursday. He did not ask his current employers for permission to make the trip.
Vermeulen is currently sidelined because of a neck injury and will miss Saturday's match against the Brumbies. He is also in doubt for a possible semi-final next weekend.
The No 8 has signed a three-year contract with the European champions and will join them after the World Cup.