Marconnet, a regular for Les Bleus when fit, is still some way short of recovering fully from the broken leg he suffered on a skiing holiday during the RBS 6 Nations Championship earlier this year.

The Stade Francais star still hopes to be ready for the start of the World Cup, which begins on September 7, but time is running out and Les Bleus already have one eye on his replacement.

Perpignan prop Mas will take part in scrummaging practice this week, acting as cover for Marconnet, and is set to become a permanent member of the squad should Marconnet be forced out of World Cup contention.

'Nicolas has responded with enthusiasm,' said Jo Maso, France's team manager.

'It allows Nicolas to be with us, to live with his friends for a bit and keep the links alive with the squad.

'That is important, not knowing for sure the date Sylvain will be ready to play again.'
Philippe Landreau, the surgeon who operated on Marconnet following the prop's accident in March, insists the prospect of his patient returning by the start of September 'remains conceivable'.

'We are confident, but this injury isn't a small thing,' Landreau said.

'There are often setbacks when you ask the body to undertake such intensive training.

'The consolidation of the fracture is good. He jogged last week, but as is often the case after such an injury, there are problems with the joints.

'He is troubled by his left ankle. I think it's an inflammatory reaction. The goal of September 7 remains conceivable but it all depends on how his ankle reacts.'

The experienced Marconnet is France's first-choice prop and it would represent a massive blow to the hosts' chances of success in the World Cup should he be ruled out of the tournament.

Mas, who is on Les Bleus' stand-by list for the showpiece, has been training with his cousin and Perpignan club doctor Olivier Lambert over the summer.