PSG's 9-0 thrashing of Guingamp on Saturday was soured by midfielder Marco Verratti suffering a sprained left ankle, and Neymar sustained a problem in their latest success.
The Brazil forward received treatment for an issue seemingly sustained after a challenge from Strasbourg midfielder Moataz Zemzemi and, though Neymar returned to the pitch, he withdrew himself in the 62nd minute and was consoled as he made his way down the tunnel.
Thomas Tuchel's side had been 1-0 up at the time thanks to Edinson Cavani's early goal, and Angel Di Maria's 80th-minute volley made sure of their progress to the last 16.
PSG went ahead inside four minutes, Cavani placing home after Eric Maxim Choupo-Moting gathered Thiago Silva's long ball.
After going close with a pair of free-kicks, Neymar somehow poked wide in front of an open goal after sliding to reach Di Maria's squared pass.
Cavani's downward header from a corner was clawed away by Matz Sels, who kept out Neymar's effort and saw Di Maria's follow-up attempt hit the post before half-time.
Neymar's eventful evening continued when he suffered his apparent injury when trying to fend off Zemzemi, who attempted to tackle the Brazilian three times before the referee's whistle went.
The PSG forward was unhappy with the rough treatment meted out and got a form of revenge when he flicked the ball over the Strasbourg midfielder before firing wide from the resultant set piece.
However, Neymar left the pitch shortly after and his evening ended with 28 minutes still to play.
It appeared to have an adverse effect on Tuchel's men, who barely created anything until Di Maria reached Julian Draxler's back-post cross to make sure of the win 10 minutes from time.
That killed off any hope of a Strasbourg fightback and also allowed Tuchel to introduce Jese Rodriguez from the bench for his first PSG appearance since December 2016.
What does it mean? PSG left with Neymar fears
Neymar sustained his injury with less than three weeks to go until the first leg of PSG's Champions League last-16 tie against Manchester United. A fractured metatarsal and sprained ankle suffered last February ensured he missed the rest of the domestic season. A similar period on the sidelines would be a significant blow to PSG's continental hopes.
No Mbappe … then no Neymar, no problem.
Tuchel opted to leave Kylian Mbappe out of his matchday squad and even after Neymar came off his team still had plenty of firepower. Di Maria looked the most dangerous throughout and got his reward when Draxler picked him out at the back post to score the second with 10 minutes to go.
Zemzemi endures night to forget
He may have injured Neymar but Zemzemi was made to look foolish when the PSG forward responded by flicking the ball over his head moments later. Moreover, it was Zemzemi's dreadful clearance that allowed the home side to score their second and clinch the tie.
Ligue 1 leaders PSG, who are 13 points clear with two games in hand, may be without Neymar when they entertain Rennes on Sunday before a trip to Lyon. Fifth-placed Strasbourg will hope to get back to winning ways in the first of back-to-back games against Bordeaux.