French football under microscope after Lyon team bus attack
Sunday's Ligue 1 match between Marseille and Lyon was postponed after the attack on the bus on its way to the Velodrome.
Grosso's face was left bloodied and his assistant Raffaele Longo was also injured. A club source said Grosso had also been experiencing dizzy spells.
TV pictures showed Grosso with a bandage on his head as he emerged from the stadium's medical room.
A photo circulating on X, formerly known as Twitter, appeared to show Grosso lying on a stretcher with a cut above his left eye.
The match was postponed at Lyon's request despite even though the stadium was already half full.
'Up to the clubs'
It was the latest incident in an already trouble-scarred season in France.
Sports Minister Amelie Oudea-Castera said the incidents were "unacceptable" and called on the clubs to take firm and swift action.
"if it is proved that supporters were involved... then clubs cannot remain on the sidelines of that," she told France 2 television.
"All the authorities in sport must be made responsible," she added.
Interior Minister Gerald Darmanin said nine people had been arrested as a result of the incidents.
He said 500 officers had been on duty for the match between two of French football's best-supported clubs and so "there was no fault" on the part of the police.
"It is up to the club to manage its supporters," he said.
As the incidents took place outside the stadium, the clubs are not, in theory, liable.
In a related incident, Lyon fans were said to have aimed racist chants at their Marseille counterparts on the approach to the stadium, which could be punishable under the French league's rules.
The French league's director general Arnaud Rouger said: "This is not our responsibility, but as with any incident we stand side by side with the government and I fully support the words of Gerald Darmanin who has called for a stronger penalties for the perpetrators of these particularly serious incidents."
Marseille club president Pablo Longoria said he was disgusted by the attack on the Lyon bus.
'Unacceptable circumstances'
"These are completely unacceptable circumstances," he said.
"My first thought is for Fabio Grosso, someone I respect and have known for a long time. I went to see him as soon as I arrived at the stadium, I saw how he was."
The timing of the incidents is highly damaging for French football authorities who are trying to negotiate a new deal TV rights deal.
Earlier this month, a match between Montpellier and Clermont was abandoned after a firecracker was thrown on the pitch and four men were arrested for attacking the Rodez goalkeeper at a Ligue 2 game in Bordeaux.
The French league also took action against Paris Saint-Germain for homophobic chants by their supporters in the home match against Marseille on September 24.
Last season, Nice were docked a point after their home game against Marseille was abandoned because of fan violence, there was a pitch invasion when Lille visited Lens and battles in the stands when Marseille visited Angers.
In January, Paris FC and Lyon were both thrown out of the French Cup after violence forced their tie to be called off at half-time.
With global stars Lionel Messi and Neymar having left Paris Saint-Germain, the images of a bloodied Grosso and a postponed match as a result of supporters' violence will do little for the game's marketability in France, where the league is aiming to drive the rights sale up beyond one billion euros ($1.06 billion).