McDonald’s character is the ex-wife of Sam (played by Taye Diggs) and best friend to Addison (played by Kate Walsh).
The 42-year-old actress left “Private Practice” to spend more time with her 11-year-old daughter Zoe in New York City.
On the series, Naomi left Seaside Wellness in Santa Monica, Calif. at the end of season four and joined Fife (played by Michael Patrick Thornton) in New York.
Details on why McDonald’s character is returning are being kept secret.
“Private Practice” will air its final episode after six seasons in late January 2013.