Lyon has overcome a poor start to move within two points of French leader Lille, but there is increasing concern at the club that the defense concedes too many soft goals.
Lyon let in two goals in seven minutes in Tuesday's 2-2 home draw with Hapoel Tel Aviv in the Champions League. Claude Puel's team has leaked 31 in 23 games overall this season - keeping just five clean sheets.
Ahead of Sunday's home match against Toulouse, the club president's adviser, Bernard Lacombe, made his feelings known with some angry comments after the draw with Hapoel.
"It's unacceptable," he said. "Even if you're not playing against Real (Madrid) or Barcelona, you've got no right to leave so much space."
Lacombe, once a prolific striker for Lyon, has long advised president Jean-Michel Aulas on topics ranging from tactics to player recruitment.
Lacombe's influence is considerable and sometimes seems to cross over into Puel's realm.
Speaking on the club's TV channel, Lacombe said the defensive record would be even worse if not for No. 1 France goalkeeper Hugo Lloris.
"It's not very reassuring to have conceded 31 goals in 23 games, when you take into consideration how many saves Hugo Lloris has made," Lacombe said.
Seven-time former champion Lyon made a dreadful start to the season, dropping to 18th place after eight rounds, when it was 10 points off the lead and most fans were calling for Puel's sacking.
At the time, Lacombe did not publicly back Puel - they reportedly have tense relations - but Aulas did several times and things have improved.
Now, after 16 rounds, Lyon is in fifth place with 26 points. Lille has 28, Paris Saint-Germain and Rennes have 27. Defending champion Marseille also has 26, but is well ahead of Lyon on goal difference.
The standings have changed regularly this season, and with the top four teams all away from home they could do again after this weekend.
Lille plays at last-place Arles; PSG is away to Valenciennes, and Marseille is at Auxerre on Saturday. Rennes goes to inconsistent Bordeaux in Sunday night's game.
The return to scoring form of strikers Lisandro Lopez and Bafetimbi Gomis has boosted Lyon's attack, but the central midfield and the defense are both lagging behind.
Lyon signed Dejan Lovren in January in a deal worth ?9.5 million ($13.8 million), but the 21-year-old Croatia defender has failed to settle alongside either offseason signing Pape Diakhate or veteran Cris.
Puel would be concerned that Cris and Diakhate have not looked convincing alongside each other, and were at fault for both of Hapoel's goals by leaving far too much time and space to the Israeli team.
"It makes me laugh a bit. Every time, the finger's pointed at us," Diakhate said.
Cris, however, does not see the funny side.
"We made some weird mistakes in defense," he said. "We can't make mistakes like that."
In midfield, France playmaker considers to disappoint after joining from Bordeaux for ?26 million ($34 million). Ball-winner Jeremy Toulalan seems bereft of confidence since coming back from France's World Cup debacle, and Cameroon international Jean II Makoun is barracked by fans when the team plays at home.
"I'm disappointed. The problem isn't just the defense," Lacombe said. "You can only win the ball back if you play as a team."
PSG is the team in the best form and is finally playing attractive football after years of struggling.
Brazilian midfielder Nene continues to provide the inspiration, and already has 13 goals this season.
Since losing three straight games at the end of August, PSG has lost only once in the last 19 games overall, scoring 11 in the last four.
In Saturday's other games, it is: Brest vs. Montpellier; Caen vs. Nice; Lorient vs. Lens, and Nancy vs. Sochaux.
Monaco faces Saint-Etienne in Sunday's other match.
