UPDATED: Maura Tierney To Undergo Surgery For Breast Tumor

Maura Tierney promotes 'Parenthood,' May 2009 Getty ImagesAccess Hollywood

LOS ANGELES, Calif. -- Maura Tierney is undergoing a "medical evaluation," resulting in the postponement of production on her new NBC show, "Parenthood," the network confirmed on Saturday.

Work on the show, which was set to premiere this fall, has been postponed for eight weeks "due to a medical evaluation that valued cast member Maura Tierney is undergoing," NBC said in a statement.

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NBC declined to give out further details on Maura's condition, but on Monday, Maura released her own statement, in which she revealed she is having surgery.

"I have discovered a tumor in my breast, which requires surgery," Maura said in a statement. "I will not know either my exact diagnosis or course of treatment until that surgery is performed."

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Maura said her medical practitioners have given her good news and she is appreciative of the well wishes she has received since the news was announced.

"My doctors have all assured me this is a very treatable condition," her statement continued. "I'm very optimistic as to the outcome and want to thank everyone who has sent positive thoughts and support. I look forward to going back to work soon."

Promos for "Parenthood" have already been airing on NBC, but the show will now start midseason.

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Instead, "Mercy," a drama starring Michelle Trachtenberg, Taylor Schilling and Jamie Lee Kirchner, will premiere this fall.

Maura's role as Sarah, one of four adult children, on "Parenthood," follows up her decade long stint as nurse Abby Lockhart on NBC's medical drama, "ER."

"Parenthood" also stars Peter Krause, Dax Shepard and Craig T. Nelson.

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