bench·warm·er 
/ˈbɛntʃˌwɑɚmɚ/ noun
plural bench·warm·ers /ˈbɛntʃˌwɑɚmɚ/ noun [count] US, sports : a player who is not among the best players on a team and does not often play : a reserve player who is usually on the bench
▪ I played a little, but mostly I was a benchwarmer.
▪ I played a little, but mostly I was a benchwarmer.
