bench strength

/B EH1 N CH S T R EH0 NG K TH/
noun
  1. 1

    The quality and number of players available to substitute during a game.

  2. 2

    The competence and number of employees ready to fill vacant leadership and other positions.

    โ€œbuilding an organization's bench strength through management trainingโ€

Source: https://en.wiktionary.org/wiki/bench%20strength