The defensive specialists role is subtly different than the libero. The DS, as its known, sits in the back row in one of the corners and is responsible for hits at the outside lines and, like the libero, digs spikes to continue rallies.

In the volleyball rotation, however, adding or replacing the defensive specialist counts as one of the teams 18 substitutions, and the DS must move through the rotation. The libero, however, can substitute for any back row player without penalty. The DS, on the other hand, usually subs for a front row player such as the middle blocker to provide more ball skills on the floor at any given time. This means a defensive specialist plays about 75 percent of the match, not the entire thing like the libero.

As the name implies, the defensive specialist isnt really concerned with offense. Two or three players in the front row launch hits over the net, whereas the setter and libero set up offensive attacks. The DS plays in the back row, reads the hitters, calls out what theyre doing and tries to keep the ball in play.