Nice's Ivorian international striker Jeremie Boga (27) has suffered a "serious muscle injury" to his right thigh, coach Franck Haise said on Saturday, which the club estimate could take months to heal.
"This year he has injured himself in three or four different places in the muscle area, I can't explain," said Haise.
France-born Boga picked up the injury ahead of last Thursday's trip to Brussels for a Europa League game against Union Saint-Gilloise which the French club lost 2-1.
According to his coach, Boga still needs additional tests to determine if surgery is required but club sources have estimated the forward will need at least three months to recover.
Boga is one of 10 Nice players who are absent for the team's Ligue 1 trip to struggling Montpellier.
Nice are sixth in the league table.