If both or anyone of Shadab or Nawaz plays today, their career will depend on todays performance.
Shadab and Nawaz both had poor performances last time against India and fans were furious to the point that they wanted them out of the World Cup squad. But Babar protected them. Now if Usama Mir plays in place anyone of the player, that player's career will be protected for the time being, but if anyone of these two or both play and get smacked for runs again, that would be the end of their career.
Babar's captaincy will also depend here. Especially if lack of performance of Pakistan comes from either of these two spinners. Fans really want Usama Mir to play because no one expects Shadab or Nawaz to do anything here.
Ideally, I would drop Nawaz for Usama Mir.
Anyways, if both play or anyone of them plays, I hope they can give a good performance and save their career. Today is the day, their careers will be on stake.