1) Allayer 2) Easer 3) Finisher 4) Hurler 5) Locum 1) Backup 2) Backup man 3) Bullpen figure 4) Certain pitcher 5) Compeer 6) Equal 7) Fill-in 8) Fireman of a sort 9) Late-game pitcher 10) Late-inning pitcher, often 11) Match 12) Peer 13) Relief 14) Stand-in 15) Substitute 
• (n.) One who, or that which, relieves.
Re·liev'er noun One who, or that which, relieves. 
[n] - a person who reduces the intensity (e.g., of fears) and calms and pacifies 2. [n] - a pitcher who does not start the game
Refers to a relief pitcher or softball pitcher who makes an entry in the game after the starting pitcher is eliminated because of injury, incompetence, or any other factor.
noun a person who reduces the intensity (e.g., of fears) and calms and pacifies; `a reliever of anxiety`; `an allayer of fears`relief pitcher noun a pitcher who does not start the game