'Private Practice' showrunners exit series

Robert Rovner and Jon Cowan have stepped down as executive producers/showrunners on ABC's drama "Private Practice."

Rovner and Cowan took the reins of the "Grey's Anatomy" spinoff after the first season and steered the series the past two seasons, which saw Kate Walsh and company excel in the ratings after moving to Thursdays behind "Grey's Anatomy" midway through Season 2.

There will be no immediate replacement for Rovner and Cowan this season as the two are departing with all episode stories for the rest of the season already developed.

"Grey's" and "Practice" creator/executive producer Shonda Rhimes will continue to supervise all creative and production aspects of the spinoff as she has done throughout the show's run.

While ABC has not handed out renewals to its returning series, "Practice" is expected to be back in the fall.

Meanwhile, ABC Studios confirmed Wednesday that Katherine Heigl's final appearance on "Grey's" aired Jan. 21, four months before the show's season finale in May. The studio said Heigl was ending her run as Dr. Izzie Stevens by "mutual agreement"; the actress recently adopted a daughter.

Her departure was first reported by EW.com.