Need one MB to play defense

Question
Is there a good way to play with a Libero, still have one of our MB play backrow and keep the Libero on the court as much as possible? Our team encountered an injury issue and had to move an OH to the middle. Problem is we don't want to lose his defensive skills. Our other middle doesn't really have any defense skills so playing him around would not be preferred. Any advice you could give on this situation would be great. Thanks!
Dan

Answer
I'm a little confused by your question.  It seems that you lost one MB and have moved an OH to cover MB and you want to keep that MB in the game that MB rotates to the backrow.  I infer that normally you substitute your MB's out and have the Libero fill their positions.  

The Libero is the perfect solution for this because a Libero can substitute in for not just one but as many different positions as you want.

So, given your situtation.  You want to keep the MB that used to be an OH in the backrow.  This sounds good.  You could sub in the Libero in another position or not at all.  When the MB with the less-than-good defense skills rotates to back row, go ahead and throw in the Libero.  Remember, a Libero substitution does not count as a normal subsitution and gives you a good amount of latitude when deciding how to manage your defense.