Softball
Designated player

In fastpitch softball, it is common for teams to use a designated player in the lineup; this player, which functions like the designated hitter in baseball, hits in place of one of the position players but does not play defense.

Unlike a designated hitter, a designated player can also become a temporary defensive substitute, and the player substituted by the designated player can return to their original position at a later point in the game. However, the only player that can be substituted as an offensive replacement (pinch runner or pinch hitter) is the defensive player the designated player originally replaced, known as the "flex".

At any time, the designated player can be substituted back into the lineup in the place of the flex player, but once taken out, the designated player cannot take the place of any other player in the lineup.
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