The first recast (and rumored only) on the Grey's Anatomy spin-off Private Practice has happened according to Michael Ausiello. Addison's best friend, Dr. Naomi Bennet was originally played by Merrin Dungey and will now be played by Tony Award winning actress Audra McDonald.
He also said:
Earlier this month, there were rumblings that execs had concerns that the Private lineup wasn't perfect, especially after some of the actors didn't "pop" with audiences. "Grey's Anatomy was cast off whoever seemed to fit the parts best and have good chemistry," says a well-placed source. "The spin-off was cast with actors the network and studio already had under contract."
I can think of a few other characters they can get rid of to make the show more interesting. They need to get rid of Amy Brennenman and Paul Adelstein because they characters were annoying and waste of stroyline. This show is large enough ensemble cast as it is, will anyone miss them if they were gone?