Tipped as the most likely challengers to Paris Saint-Germain this season, Monaco and Lyon have been hit by injuries and inconsistency as they prepare to meet in the principality on Friday.

Lyon were runners-up last season in Ligue 1 but come into this weekend's visit to the Stade Louis II in sixth place as they struggle to adapt to losing France's reigning young player of the year Nabil Fekir to a serious knee injury.

France playmaker Clement Grenier is another long-term absentee and their attacking options were further reduced this week when teenage striker Aldo Kalulu was ruled out for two months with an ankle injury.

French league rules allow clubs to sign a 'medical joker' outwith the transfer window to replace players ruled out with long-term injuries, but Lyon president Jean-Michel Aulas continues to rule out any possibility of bringing in a new face.

"At the moment we have no plans to bring in a medical joker, for several reasons," said Aulas.

"We have a good squad and players like Clement Grenier will come back. There are also players in the youth squad. And it is difficult for the morale of a player when he comes back and sees that another player has been signed and is playing in his place."

That may not please coach Hubert Fournier, whose side have a tricky trip to Russia to face Zenit St Petersburg in the Champions League next week.

Lyon beat Reims 1-0 in their last outing before the international break but have not yet won back-to-back games this season, although Monaco are still looking for their first win at home in the league this season.

And the principality side's coach Leonardo Jardim has a host of selection problems, with defenders Andrea Raggi and Ricardo Carvalho suspended and Malian midfielder Adama Traore having been ruled out with a fractured ankle.

"I don't know yet who will be fit to play on Friday," admitted Jardim, whose side are 10th in the standings, a distant 10 points behind unbeaten league leaders PSG.

The reigning champions will look to extend their unbeaten start to the campaign when they face Bastia in Corsica on Saturday, although they could be forgiven for having one eye on next midweek's glamour Champions League clash at home to Real Madrid.

Paris, who beat bitter rivals Marseille 2-1 a fortnight ago and are five points ahead of the chasing pack, saw centre-back David Luiz injure his left knee playing for Brazil in a World Cup qualifier against Chile last week, although they are hopeful he will be back in time to face Madrid.

In addition, Salvatore Sirigu is set to return in goal after Kevin Trapp -- who usurped the Italian in the pecking order after arriving from Eintracht Frankfurt in the summer -- suffered a hamstring injury in training last week.

Paris lost 4-2 in Bastia last season, but the Corsicans are not in great shape coming into this match, having lost five of their last six games.

Angers, who were promoted last season, sit surprisingly in second place at the moment and visit struggling Toulouse on Saturday, while Caen in third go to Reims.

Saint-Etienne had been in second place before losing their last two games so will be looking to bounce back at home to bottom side Gazelec Ajaccio.

Marseille took encouragement from their performance against PSG, even in defeat, but are just four points clear of the relegation zone before hosting Lorient at the Stade Velodrome on Sunday.

Fixtures (kick-offs 1800 GMT unless stated)