To take the place of; replace.
To profit; benefit; serve; avail.
To help, assist.
To serve as a replacement (for someone or something).
To remove (a player) from the field of play and bring on another in his place.
To use in place of something else, with the same function.
To use X in place of Y.
To use Y in place of X; to replace X with Y.
A player who is available to replace another if the need arises, and who may or may not actually do so.
A replacement or stand-in for something that achieves a similar result or purpose.
One who enlists for military service in the place of a conscript.