the.com/reliever

means A relief pitcher brought in mid-game to replace the starter, usually in a tight or urgent situation.

from From 'relieve,' tracing back to Latin 'relevare' — 're-' (again) plus 'levare' (to lift, to raise) — the same root that gives us 'lever' and 'levity.' To relieve someone was literally to lift a burden off them; the baseball sense, emerging in American sports writing as bullpens became specialized, simply applies that old lifting-of-burden idea to a pitcher lifting the weight off a tiring starter's shoulders.