a player who does not participate in the game but remains as a reserve

someone who is not actively engaged but is part of a group

समूह का सदस्य लेकिन सक्रिय नहीं

English Usage: In the meeting, she felt like a bench warmer, not contributing to the discussion.

Hindi Usage: मीटिंग में, उसने महसूस किया कि वह एक बेंच वार्मर है, चर्चा में योगदान नहीं दे रही।