TVSquad

Actress Maura Tierney has been forced to abandon Parenthood, the NBC ensemble series in which she was cast last spring. Tierney had been diagnosed with breast cancer, had surgery and now must have treatment – chemotherapy and radiation.

The producers had pushed back production when Tierney's health crisis arose in July, but now that her condition requires prolonged treatment, she's walking away from the project and they will move on without her.

Maura released a statement saying that she was disappointed about not being able to do Parenthood, but she was confident that she would recover and resume her career after her treatments are complete.

NBC had picked up Parenthood based on the pilot, in part because of Tierney's participation. The actress was playing a single mother with money troubles who's forced to move in with her parents. Because Maura has a great track record with NBC, especially her tenure on ER, they wanted her to stick with the show. With that in mind, NBC shelved Parenthood till mid-season, giving Tierney a chance to stay with the show. In Parenthood's place, NBC scheduled Mercy for the fall.

Parenthood will go back into production now with another actress cast in the role. "Our main concern is for her quick and full recovery," said a spokesman for the network.