Former France goalkeeper Fabien Barthez was involved in a fight with a supporter after his Nantes side moved closer to relegation with a 2-0 home defeat by Stade Rennes
Nantes president Rudi Roussillon told reporters five drunken fans had blocked Barthez's car as he was driving out of the Beaujoire stadium.
They kicked the car and banged on the windscreen and one fan tried to open the car door.
The former world and European champion then got out of his car and started trading punches with one of the fans.
Security staff moved in to separate them.
Barthez left his Nantes home by car the next morning with his children for an unknown destination.
It was not clear whether he had left for a few days or for good.
'It is a possibility', Roussillon told reporters when asked whether he feared Barthez might not return.
'Fabien is in a state of shock,' Roussillon said. 'He has been deeply affected by this assault. This is not acting. He can't cheat.
'It's hit him hard, I would even go so far as saying he's been traumatised.
'He asked us if he could go back to see his family. I hope I can get him to come back, but if he says no then I would understand.'
Whether Barthez returns at all to the stricken club is another poignant question for the Canaries' frustrated fans.
Eight-times champions Nantes are on the verge of being relegated for the first time.
The team has spent a record 44 consecutive years in the top flight since being promoted in 1963, but they are now eight points from safety at the foot of the table with four matches left.
Barthez came out of retirement in mid-December to help Nantes in their bid to escape relegation.
The bald-headed 35-year-old has, however, committed some embarrassing blunders reminiscent of his worst days at Manchester United.
He has also stirred controversy, notably after conceding a clumsy goal in a 1-0 defeat at home to lowly Sedan earlier this month.
After being substituted with an injury, he left the stadium without waiting for the end of the game.
He has been accused on several occasions of feigning injury to avoid training.
In his 14 matches with the club he has conceded 23 goals.