The actress is undergoing cancer treatments, which conflict with the show’s production schedule.
“Ms. Tierney and her doctors remain confident that the outcome of her treatments will be positive,” Tierney’s spokeswoman said Thursday. “She is deeply disappointed that she will not be able to rejoin such a highly respected, talented, fun and funny group of actors and wishes to thank Jason Katims and NBC for their patience and support.”
NBC is in the process of recasting the role.
In July it was revealed that Tierney is battling breast cancer. For more details, click here.