France coach Marc Lievremont's injury worries with regard to his squad ahead of the start of their World Cup preparation have deepened as first choice hooker William Servat was told he would have to undergo a left knee operation.

France coach Marc Lievremont's injury worries with regard to his squad ahead of the start of their World Cup preparation have deepened as first choice hooker William Servat was told he would have to undergo a left knee operation.

The 33-year-old 37-times capped Toulouse star - part of the team that captured their 18th league title on Saturday is expected to be out for between four to six weeks after undergoing the operation in mid-June, French team doctor Jean-Philippe Hager told AFP.

"He will not be able to run at best before mid-July," Hager said.

Servat will miss the opening of France's World Cup training camp which Lievremont is planning for June 28 as France build-up to the World Cup, which runs from September 9 to October 23 in New Zealand.

It leaves Lievremont without either of his preferred hookers because Stade Francais's Dimitri Szarzewski is still recovering after an Achilles tendon operation in February.

Should either of them withdraw then Perpignan's Guilhem Guirado would come into the squad.

Lievremont - who has failed to dispel the doubts harboured about him since he was the surprise choice to replace Bernard Laporte after the 2007 World Cup - also has serious worries over his props.

Thomas Domingo is struggling with a knee injury while Fabien Barcella is also convalescing after rupturing his Achilles tendon last August.

There is problems too in the centre as veteran Aurelien Rougerie has a foot encased in plaster while Maxime Mermoz is recovering from a shoulder operation.

France begin their World Cup campaign against Japan on September 10, after a two month preparatory period which sees them play two 'friendly' tests against Ireland, in Bordeaux on August 13 and in Dublin on August 20.