They're called the libero. Which they can switch out without having to sub out by the ref and wait. So its a little faster. And they're usually the best passers.
In volleyball, the libero player wears a different colored jersey. The libero is a defensive specialist who can freely substitute in and out of the game without counting towards the team's substitution limit. The unique uniform helps officials and players easily identify the libero on the court.
libero
In volleyball, the uniform is different compared to other sports because it is designed to be comfortable and allow for ease of movement, as well as to distinguish between teams on the court.
Different departments wear different colored uniforms,
red; communication blue; medical yellow; loyalty
a volleyball a net two teams and a umpire and a crowed and a uniform
blue
A uniform and knee pads and volleyball tennis shoes and sometimes ankle braces
1976
probably because the usual uniform consists of spandex shorts...
They are usually the people who aren't as good as hitting and are a little shorter. They go in and play back row for the taller hitters until they get to the front row. They alsoserve for people who aren't that good at serving :)
If the "middle man" you're talking about is the referee, then this is why he dresses differently from the rest of the players: to avoidbeing mistaken for a player.