Kylian Mbappe has started his recovery from a hamstring injury that is set to rule him out for four weeks.
The Paris Saint-Germain star pulled his hamstring during a 4-0 Ligue 1 defeat of Toulouse on Sunday and the champions confirmed he could miss around a month of action.
PSG had already lost Edinson Cavani to injury, with Abdou Diallo also having to be withdrawn in the first half after taking a blow to the head.
With Neymar left out of the squad amid continuing uncertainty over his future at PSG, Thomas Tuchel's attacking options have been limited, although Eric Maxim Choupo-Moting scored twice against Toulouse.
World Cup winner Mbappe used social media to reassure fans that he will do his utmost to be back in action quickly.
"Thank you all for your messages," Mbappe wrote on Twitter, alongside a photo of him in a swimming pool.
"I today started my rehabilitation to come back to help my club and be available as soon as possible."
Mbappe and Cavani are both doubts for the first round of group games in the Champions League, which gets up and running in mid-September.
PSG return to action against Metz on Friday but after the Toulouse clash Tuchel was unsure whether Neymar, who missed the Copa America due to an ankle injury, would be available.
Sporting director Leonardo has confirmed the Brazil superstar wants to leave the French capital amid links to LaLiga giants Real Madrid and his old club Barcelona.
PSG and Barca are reportedly set to conduct talks over a potential deal for Neymar on Tuesday.