Olympique Lyon have been hit by a series of groin injuries with keeper Hugo Lloris, defenders Jean-Alain Boumsong, Aly Cissokho, Mathieu Bodmer, Cleber Anderson, Cris, midfielders Cesar Delgado, Jeremy Toulalan, Kim Kallstrom and striker Lisandro Lopez all suffering from the same problem before their trip to arch-rivals St Etienne on Saturday.
"We have been asking ourselves a lot of questions to solve this problem," coach Claude Puel told L'Equipe on Friday.
"But every case is different. It is hard to find a reason."
Captain Sidney Govou said: "No one cheats in this squad. The good thing is that everybody gives everything during training but the downside is that when some players do not feel very well, they do not say it."
Boumsong and Bodmer have been ruled out of the St Etienne trip. Deldago and Lopez are doubtful while the others are expected to be fit.
French international keeper Mickael Landreau will start Lille's game at bottom club Grenoble on Saturday four months after tearing a ligament in his knee.
"He is ready to play. He has the experience to adapt," coach Rudy Garcia told reporters.
Ludovic Butelle, who had deputised for Landreau since the start of the season, will sit on the bench.
South Korean forward Park Chu-young is set to miss Monaco's trip to leaders Girondins Bordeaux because of a knee injury, L'Equipe reported on Friday.
Frederic Nimani is expected to deputise for Park, who helped Monaco move to second in the standings by scoring three goals and setting up two this season.
Girondins Bordeaux defender Henrique has been ruled out of the leader's game against Monaco with a knee injury, the club said.
France striker Andre-Pierre Gignac said he is almost fully fit for Toulouse's trip to Olympique Marseille on Saturday after struggling with groin problems.
"I have been in treatment three times a day. I am on the right path since I don't feel any pain anymore," Gignac told L'Equipe's website.
Marseille midfielder Benoit Cheyrou, who has been impressive this season, is a doubt for the Provence side's game against Toulouse with a groin injury, OM said on their website.
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