He will start with a mixture of bench and squad players, maybe use a couple of guys like Kolasinac or Bellerin who don't need much rest and have the likes of Sanchez on the bench in case they are needed.
Losing this game wouldn't kill our chances of going through but losing at Chelsea (which will probably happen anyway seeing as they have the easiest of games at home in the CL) will leave us uncomfortably close to the relegation zone with more than an eighth of the games played.