Bumrah has been ruled out of competitive cricket for an indefinite period due to stress related injury in his back. Shami had last played in T20 internationals during the last edition of the ICC T20 World Cup in the UAE.

from Times of India https://timesofindia.indiatimes.com/sports/cricket/icc-mens-t20-world-cup/indiat20-world-cup/mohammed-shami-replaces-injured-jasprit-bumrah-in-indias-t20-world-cup-squad/articleshow/94861272.cms