Liz Brixius (left) and Linda Wallem consult with producers/Showtime

First the good news: Showtime has renewed "Nurse Jackie" for a fifth season. The bad news: Showrunners Liz Brixius and Linda Wallem, who both attended University of Minnesota before creating the series, are being replaced.

Clyde Phillips, who previously supervised "Dexter," will be in charge when shooting on the Edie Falco dramedy in late 2012.

Why a new boss? It's not unusual for showrunners to quit or be replaced after so many years, but this case might be a bit more unusual. Speculation is that new Showtime management forced Brixius and Wallem to put Nurse Jackie in rehab this season, something the duo told me years ago that they were reluctant to do anytime soon.

Could it be that they hated the idea? Jackie's rehab stint was remarkable short, so much so that one coudl speculate that Brixius and Wallem wanted to get over it as fast as possible.

Eager to see what both "Nurse Jackie" and this dynamic writing duo do next.