The idiom Waiting in the Wings means there is someone in the background, but close and ready to act on a little chance.
It means taking over someone's else position or power.
In Bollywood, there are always plenty of actors waiting in the wings ready for a chance to act in a movie.
Hoping that a member of the hockey team would drop out and he would get a place on the team, deepak Thakur was waiting in the wings.
Mr. Madan retires as accountant after 6 months, and Mr. Ravi is just waiting in the wings.