Marseille coach Elie Baup has confirmed that Andre-Pierre Gignac has fractured "the fifth metatarsal in his left foot" during the side's 1-0 defeat against Troyes.
Gignac, 26, departed the game in the 20th minute following a duel with Florian Jarjat, and says he knew straight away the injury was a bad one.
"I felt that it was not going well," the striker explained. "I immediately felt the pain. I knew it was broken."
On top of losing the game, the injury to Gignac was another blow for Baup who said exact return date has not yet been considered. "This is another negative point," he told OMTV, "but we cannot yet know the duration of the unavailability."
Gignac also told OMTV: "This is not good news. It's like that, it is part of the life of a footballer, but it is often bad luck for me, and doubly because we lost tonight." He added on Twitter: "I am a fighter! I'll come back even stronger!"
The France international had started the season convincingly, scoring five goals in his first eight Ligue 1 games of the season.