Second string and Stand-in

Second string noun - A squad of players that are available either individually or as a team to relieve or replace the players who started the game.

Stand-in and second string are semantically related In some cases you can use "Stand-in" instead a noun phrase "Second string".

Stand-in noun - A person or thing that takes the place of another.

Second string and stand-in are semantically related in substitute topic. Sometimes you can use "Second string" instead a noun phrase "Stand-in".