Marseille's Lucho Gonzalez will be out of action until the start of September with a fractured collarbone.

The Argentina international, who signed for OM this summer for a club-record fee of 18million euros, was taken to a hospital in Valence after falling heavily on his left shoulder at the start of the second half of a friendly against St Etienne.

Tests have revealed the extent of the injury and he has been ruled out for between four and six weeks, meaning he will miss the start of the new Ligue 1 season.

"His return to competition is envisaged in the first fortnight of September, which means an unavailability of four to six weeks," read a statement released on OM's official website www.om.net.

Gonzalez suffered the injury after battling for the ball with St Etienne forward Kevin Mirallas in the 54th minute of last night's pre-season match, which OM won 1-0.

Gonzalez's left arm was put in a sling and he was taken immediately to hospital.

It is a cruel blow for the midfielder, who has impressed in OM's friendly games since moving from Porto.

While coach Didier Deschamps is blessed with strength in depth in midfield, having signed Stephane M'Bia, Fabrice Abriel and Edouard Cisse over the summer, marquee recruit Gonzalez is his lynchpin.

Abriel, who joined the Mediterranean side on Tuesday from Lorient, is likely to replace Gonzalez as the team's playmaker in August.

Marseille's first Ligue 1 match of the new season is against Grenoble away on August 8.

Deschamps was disappointed to lose a player of Gonzalez's quality for the first month of the season but has backed the midfielder to bounce back.

"It is a hard blow first of all for the player, because he is clearly someone who has a lot of desire and is important," Deschamps told reporters at OM's training base today.

"He was starting to get stronger, even more than I'd expected after two months of inactivity. He was starting to show something special even if it was far from what he can do.

"The most important thing is that he can heal well without losing ground physically, so he can be ready as early as possible.

"He is disappointed. But I saw him a short time ago and he is keeping his smile.

"It's just a hitch and he will come back stronger."