Australia scrum-half Jake Gordon has been forced to leave Top 14 side Toulon after suffering concussion weeks after his arrival as cover for the Rugby World Cup, the French club said Tuesday.

"It's a fairly significant concussion which cannot allow him to assume his role as World Cup cover," Toulon manager Pierre Mignoni said. 

"Unfortunately, he has between four to eight weeks (out), his career is not in question but he is not able to be on the pitch immediately."

Gordon, 30, made the last of his 20 Wallabies appearances in November but has been omitted from their squad for the ongoing Rugby Championship.

Earlier this year, Gordon signed a new deal with Rugby Australia until 2025, when the British and Irish Lions tour takes place.

The Waratahs half-back arrived on the Cote d'Azur on a temporary basis with Baptiste Serin away with the France set-up and Ben White with Scotland preparing for the World Cup, which begins on September 8.

He had trained with the Toulon group for a few days before joining Australia where he took a knock in a friendly against Tonga. 

"It's a shame because we discovered a very endearing personality but the collaboration cannot be done," said Mignoni. 

Toulon is therefore still on the look-out for at least one player as a scrum half.

"We are looking for someone available now, it is not easy but we will find," Mignoni added.

Three-time Champions Cup winners Toulon start their Top 14 season on August 19 with the league taking a three-week break during the World Cup held in France after three rounds of domestic games.

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