Warning: This article includes an image some readers may find distressing

The attack on Lyon's team bus in Marseille on Sunday "could have been a tragedy", says manager Fabio Grosso.

The scheduled French top-flight match between the sides was postponed after the visitors' bus was hit by rocks on its way to the Stade Velodrome.

Grosso and his assistant Raffaele Longo both sustained facial injuries after being hit by projectiles.

"I hope with all my heart that it can be a lesson for our future," Grosso, 45, wrote on Instagram.

"What happened on Sunday evening could have been a tragedy. It certainly was for the sport and for all those who love it."

Former Italy international Grosso needed 12 stitches, and was unable to take charge of training on Tuesday.

An image of the World Cup winner was used as a striking front cover of French national newspaper L'Equipe on Monday, and the attack drew widespread condemnation from both inside and outside the game.

Nine people have been arrested in connection with the incident.

And French news agency AFP reports that Lyon have requested the rearranged fixture at Marseille is played at a neutral ground.

"At the moment, the safety conditions necessary to play in Marseille have not been met," Lyon's general manager Vincent Ponsot said on the club's TV channel.

"We have to play at a neutral ground. What we want is for the safety of our players to be guaranteed."