Marseille have revealed that Mathieu Valbuena could be missing for up to six weeks after injuring his shoulder in this evening's 1-0 defeat to Lille.
The 29-year-old was substituted in the 79th minute at Stade-Lille Metropole and looks likely to miss at least the next three Ligue 1 games.
The French international will also miss next week's final Champions League match at home to Borussia Dortmund.
"He will be sidelined for an estimated four to six weeks," read a statement on the club's official website.
"He will undergo further examination [on Wednesday]."
Les Phoceens - currently fourth in Ligue 1 - have lost all five of their matches in Europe this season.