The libero is impossible to miss when watching a volleyball match. Like clockwork, a first-time viewer of the sport will ask “Why is that player wearing a different jersey?” The answer oftentimes being: “That’s the libero.”

But what exactly does the libero do?

The libero can often be thought of as an extension of the defensive specialist. Before getting into that, though, let’s start with the rules that govern the position.

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The rules of the libero

Per the NCAA rules book for women’s and men’s volleyball, the libero is strictly a back-row player and can only be replaced by the same player it replaces. Also, a coach can only designate one libero per set.

For most teams, the libero is not a starter. At the beginning of matches before the first serve, the libero will normally replace a player in the starting lineup. That player becomes the only player that can replace the libero. (There is normally one official tracking the libero substitutions during a match.)

The libero, also according to the rules, cannot “complete an attack hit” if the ball is above the net and it cannot perform an overhead set in front of the attack line — commonly called the 10-foot line — while still having…