Florian Thauvin is expected to be out until after the winter break, so can André Villas-Boas's Olympique de Marseille side enjoy success without their World Cup winner? First up is a trip to AS Monaco on Sunday.
AS Monaco - Olympique de Marseille
Marseille's hopes of competing for a top-three finish and a return to the UEFA Champions League have been dealt a huge blow with the news that Thauvin must undergo surgery on an ankle injury that has troubled him in recent months.
The 26-year-old was initially struck down by the problem late last season, before spraining the ankle in a friendly defeat against Rangers in August. He returned to action as a substitute in the 1-0 win over AS Saint-Etienne just before the recent international break, but the problem has not disappeared and now he will undergo an arthroscopy.
The French international winger is not expected to play again in 2019, and Villas-Boas will now have to find a way of replacing Thauvin without making a new signing - the transfer window closed on September 2.
Thauvin has been Marseille's top scorer in each of the last two seasons, and has netted a total of 53 league goals since the start of the 2016-17 campaign. However, OM can count on Darío Benedetto, with the Argentine international striker settling into life in France and fresh from scoring the winner against Saint-Etienne a fortnight ago.
Watch: Benedetto downs Saint-Etienne
That was his second goal in as many matches, both of which have been won by Marseille. Prior to that Benedetto missed a penalty in a 0-0 draw away at FC Nantes, but his form is improving along with that of his new side.
"Obviously I needed some time to adapt in order to feel completely at ease and grasp the speed of the game, which is faster, more sustained. But now I feel really good," Benedetto said in an interview with sports daily L'Equipe.
Rongier ready for debut
OM will also look to their latest signing for a lift, although Valentin Rongier is unlikely to provide the goals in Thauvin's absence. The 24-year-old only scored eight times in total from midfield over the last four seasons with FC Nantes before moving to the Orange Vélodrome on a five-year deal in a transfer that could be eventually be worth €15 million to his old club.
"This is a club with a huge amount of history, the only one to have won the Champions League. In the current squad I know Morgan Sanson a bit and I have played against all the others. I am going to try to integrate as quickly and as easily as possible," said Rongier, whose move fell through on transfer deadline day but eventually went through 24 hours later because rules allow each Ligue 1 Conforama club to make one emergency signing after the window has shut.
Watch: Slimani brace but Monaco held again
Rongier is set to make his Marseille debut at the Stade Louis II against a Monaco side who are still searching for their first win of the Ligue 1 Conforama campaign. The principality side have just two points to their name so far and twice threw away the lead in a 2-2 draw at RC Strasbourg Alsace last time out.
Augustin's lesson learnt
Not including players returning from loan spells, Monaco made 11 new signings over the summer. Seven of those recruits featured against Strasbourg, while the 17-year-old left-back Arthur Zagre was an unused substitute after joining from Paris Saint-Germain.
The last players to arrive were two more loan signings, with former PSG striker Jean-Kévin Augustin returning to France from RB Leipzig and midfielder Tiémoué Bakayoko coming back to his old club from Chelsea. This weekend will also see Rubén Águilar return from suspension along with Cesc Fàbregas, who made his Ligue 1 Conforama debut in a 1-1 draw in Marseille in January.
Augustin arrives to help Monaco get over the departure of Radamel Falcao, who ended a six-year association with the club by moving to Galatasaray.
"I had discussions with Nice but I am delighted to be at Monaco. I played at PSG but I left very quickly. I have learnt from my mistakes and thanks to that I know now what is good and what is bad," Augustin said at his unveiling.
Monaco: Lecomte; Aguilar, Glik, Maripan, Ballo-Touré; Martins, Bakayoko, Fabregas, Golovin; Slimani, Ben Yedder
Marseille: Mandanda; Sakai, Kamara, Gonzalez, Amavi; Rongier, Strootman, Sanson; Sarr, Benedetto, Payet