The way he was introduced to attack after all the resources, its safe to say that Captain doesn't trust him much nowadays.
And the way Kuldeep bowling he's not posing any threat to batsmen when compared to Ashwin-Axar duo, guess he's in low on confidence. I hope he pick up couple of wickets here.
And Siraj dropped a Root.... Poor Kuldeep
If he doesn't have the backing of Kohli or Shastri, then his international career is essentially finished. Look at what happened to Karun Nair. He was picked in the test squad despite opposition from Kohli and scored a triple century against England. And no one knows where this guy is now. Another example is Natarajan. Kohli preferred Saini/Siraj over Natarajan, because the former pacers are from RCB. And the same thing happened. Natarajan is out of the squad now and Siraj/Saini are in.