How/when to do libero replacements?

Question
This will be my first year using a libero and had a question if it was possible for her to play 2 rotations in left back and 3 rotations in middle back.  To better break this down, she will start in the left back position for serve receive, once we win the ball, she will sub out and our left front now became our left back (she plays all the way around), after sitting for the rotation, our libero now re-enters as our middle back and goes back to serve and play her 3 positions in middle back.  She again will sub out when it comes time, and re-enter the left back position after sitting a rotation.
Also, if that wasn't confusing enough - what is exactly considered a sitting a rotation for a libero?  Would it be just for the serve rotation and can come in when we return to serve receive or does she have to wait until we serve again?
Much appreciated!

Answer
Good evening Kayla:

Thank you for visiting www.allexperts.com.

First, let me answer your questions by the National Federation rule book and the USAV rule book.  (If you use a different rule book.... maybe the NCAA .... then this may not be 100% accurate.)  
a) Everything you said is 100% legal.
b) However, I've never heard the phrase "sitting a rotation".  The phrase we always use is "sit for one rally".  So, let's say the girl who plays all the around just entered for your libero.  The other team serves.  Point scored.  A back row player looks at you and says, "GOT TO USE THE BATHROOM!"  Ok, libero replacement for her.  Opponents score another point.  Then another.  Girl comes back from bathroom, and goes back in for libero.  Opponents serve broken.  Libero goes in for MB to serve.  All of this is legal

Replacement: I highly recommend you try to train yourself to use the word "replacement" for the libero switch.  You are limited to 12 subs in USAV and 18 in National Federation.  A libero replacement isn't considered a substitute.  I know you already know that; but, being a math teacher is the homework expressions to simply, or equations to solve.  How I say it either creates confusion or prevents it.   Yeah, about 3 years ago, USAV decided "No more will call them games.  We now call them sets."  REALLY?  After 25 years, I have to change.  It's hard enough NOT calling the entire thing a "game".  haha  I had to force myself to distinguish between games and matches in volleyball.  Now, there is no more "game" at all.   Crazy.  

USAV rule difference.  If you coach USAV club ball (not AAU, not JVA), then you are free to TWO liberos..... this season is the first season for that.  It's crazy!  And I wouldn't even worry about it, unless you and/or your girls play USAV club ball.  

There's so much more about the libero.  You may know most of this, but I wanted to add it anyway.  Hope you're having a wonderful summer.  Please visit me sometime at www.coachhouser.com.  We're in the process of our 3rd camp of 11 for this summer.  Please let us know what we can do for you.   

The libero (lee-bah-ro) position, which has been in use since 2002 in international and club play, was designed to add excitement to the game of volleyball and raise the level of play. The libero was introduced as a way to keep a good defender on the floor, and not use up a coach's limited # of substitutions.  Yes, the use of the libero does not count as a substitution.  In fact, when a libero goes in, it抯 called a 搑eplacement,?to avoid being confused with a substitution.  

The libero player is an option that may be exercised by one or both teams in the match.

The libero wears a uniform that contrasts with his/her teammates' uniforms.  The style and trim of the libero抯 shirt or jersey may differ from her teammates' shorts, but in school ball her shorts must be identical to her teammates. In club ball, even her shorts can be different.

The libero is intended to be a player who specializes in defense and serve reception.  Thus she is often smaller than many of the other players on the team; but, not less athletic!  When the libero enters the match, she does so without even notifying a referee.  The replacement just happens.  The number of libero replacements in a game/match is unlimited, and the libero can replace ANY back-row player, including (in NCAA and NF) the player who is currently serving.  The USAV ball, liberos cannot serve.  

In NCAA and in NF, a different libero can be designated for each game, but the designation must be made on the lineup sheet when it is submitted before the game.  For USAV, the designation for the libero is done at the onset of the match, and can only be changed when extenuating circumstances are present.  

In NCAA and NF, the libero for one game can play as a non-libero in subsequent games. But, she must change into the same uniform as is worn by all her other non-libero teammates.

Libero playing actions
?The libero is restricted to performing as a back-row player and is not allowed to complete an attack hit from anywhere (including back row AND front row) if, at the moment of contact, the ball is entirely above the top of the net.
?The libero cannot serve, block or attempt to block.
?If a libero comes into the front row AND hand-sets a player AND a teammates contacts the ball above the level of the net (in other words, acts like a setter!), then that is illegal.  She can forearm set anyone from anywhere.  She can also hand-set any attacker if she is behind the 10' attack line.  

Libero replacements
?The player whom the libero replaced can only replace the libero.
?Libero replacements may take place only after the end of a rally or at the start of each game after the umpire has checked the starting lineup, as well as any time the ball is out of play and before the whistle for service

I copied this info in 2008 from http://www.fhsaa.org/vbg/libero.htm; but for the changes that have been made since, I have edited.  

Thank you again for visiting!
If we can do anything else for you, please contact me anytime.  
Coach Houser