Marseille are sweating on the fitness of striker Andre-Pierre Gignac after he was forced out of training with an ankle injury on Wednesday.
Gignac, 26, damaged his left ankle after being caught on the wrong end of a heavy tackle by Pape M'Bow.
The France international reportedly reacted angrily towards his team-mate and headed straight back to the dressing room.
Marseille confirmed the injury on their website: "During this morning's practice match Andre-Pierre Gignac, following a collision with Pape M'bow, had to leave his colleagues. The striker returned to the clubhouse for treatment.''
The extent of the injury is not yet known.
Gignac has hit three goals for his club this season as they sit top of Ligue 1, having won six games out of six.
Meanwhile, defender Souleymane Diawara, rebuilding his fitness following a knee-ligament injury, came through Wednesday's full training session unscathed.