The BCCI confirmed the development on Tuesday through a statement after the ICC approved Mayank’s induction.
Shankar was on Monday ruled out of the World Cup as he sustained a toe injury in the nets while batting against Jasprit Bumrah. Mayank was named as his replacement and it was approved by ICC's technical committee.
Mayank made his Test debut last December against Australia but is yet to make his bow in the 50-over format. In List-A cricket for Karnataka, the 28-year-old has played 75 games since making his debut in 2012, scoring 3,605 runs at an average of 48.71.
India will play their final group stage match against Sri Lanka at Headingley, Leeds on Saturday.