Paris Saint-Germain star Neymar was forced off due to injury during Wednesday's clash with Istanbul Basaksehir.
The Brazil international appeared to have discomfort in his left thigh in the first half of the Champions League meeting in Turkey.
Following treatment on the sidelines, Neymar indicated to head coach Thomas Tuchel that he could not continue and was replaced by Pablo Sarabia in the 26th minute.
PSG are in the middle of a packed run of fixtures, with another three matches to come in the next 10 days prior to another international break.
They face Nantes in Ligue 1 on Saturday, with a trip to RB Leipzig and another league match against Rennes to come next week.
Neymar could be a doubt for Brazil's World Cup qualifiers against Venezuela and Uruguay next month, depending on the extent of the damage done.
The 28-year-old has made six appearances in all competitions this season.
